commit 820efb3fe89e38f35499edc8a17703782f2567fc
Author: xiaoyi <xiaoyi@example.com>
Date:   Mon May 25 15:22:18 2026 +0800

    Add project documentation from API (GitHub download failed)

diff --git a/.taskfiles/backend.yml b/.taskfiles/backend.yml
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index 0000000..56db8eb
--- /dev/null
+++ b/.taskfiles/backend.yml
@@ -0,0 +1,146 @@
+version: '3'
+
+# Gradle invocation strategy:
+#   - Linux/macOS: `./gradlew` runs the POSIX shell wrapper natively.
+#   - Windows:     `cmd /c ".\gradlew.bat ..."` invokes the .bat wrapper through
+#                  cmd.exe so it inherits the user's Windows-side `JAVA_HOME`
+#                  and PATH. Routing through `bash gradlew` on Windows ends up
+#                  under WSL or Git-Bash, neither of which inherits
+#                  Adoptium/Temurin's default Windows-only Java env - gradlew
+#                  then errors with "JAVA_HOME is not set and no 'java' command
+#                  could be found".
+#
+#                  The entire `.\gradlew.bat ...` payload is double-quoted so
+#                  the leading `.\` survives mvdan/sh's POSIX backslash
+#                  stripping; cmd.exe also requires `.\` (not bare `gradlew.bat`)
+#                  because modern Windows excludes cwd from cmd's search path.
+
+tasks:
+  dev:
+    desc: "Start backend dev server"
+    ignore_error: true
+    vars:
+      PORT: '{{.PORT | default "8080"}}'
+      AIENGINE_URL: '{{.AIENGINE_URL | default ""}}'
+    env:
+      SERVER_PORT: '{{.PORT}}'
+    cmds:
+      - cmd: '{{if .AIENGINE_URL}}AIENGINE_URL={{.AIENGINE_URL}} AIENGINE_ENABLED=true {{end}}cmd /c ".\gradlew.bat :stirling-pdf:bootRun"'
+        platforms: [windows]
+      - cmd: '{{if .AIENGINE_URL}}AIENGINE_URL={{.AIENGINE_URL}} AIENGINE_ENABLED=true {{end}}./gradlew :stirling-pdf:bootRun'
+        platforms: [linux, darwin]
+
+  dev:bundled:
+    desc: "Clean + bootRun with frontend bundled into the backend (single :8080 server)"
+    ignore_error: true
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat clean bootRun -PbuildWithFrontend=true"
+        platforms: [windows]
+      - cmd: ./gradlew clean bootRun -PbuildWithFrontend=true
+        platforms: [linux, darwin]
+
+  build:
+    desc: "Full backend build"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat clean build"
+        platforms: [windows]
+      - cmd: ./gradlew clean build
+        platforms: [linux, darwin]
+
+  build:fast:
+    desc: "Build without tests"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat clean build -x test"
+        platforms: [windows]
+      - cmd: ./gradlew clean build -x test
+        platforms: [linux, darwin]
+
+  build:ci:
+    desc: "Build for CI (formatting checked separately)"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat build -PnoSpotless"
+        platforms: [windows]
+      - cmd: ./gradlew build -PnoSpotless
+        platforms: [linux, darwin]
+
+  test:
+    desc: "Run backend tests"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat test"
+        platforms: [windows]
+      - cmd: ./gradlew test
+        platforms: [linux, darwin]
+
+  format:
+    desc: "Auto-fix code formatting"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat spotlessApply"
+        platforms: [windows]
+      - cmd: ./gradlew spotlessApply
+        platforms: [linux, darwin]
+
+  format:check:
+    desc: "Check code formatting"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat spotlessCheck"
+        platforms: [windows]
+      - cmd: ./gradlew spotlessCheck
+        platforms: [linux, darwin]
+
+  fix:
+    desc: "Auto-fix backend"
+    cmds:
+      - task: format
+
+  swagger:
+    desc: "Generate OpenAPI docs"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat :stirling-pdf:copySwaggerDoc"
+        platforms: [windows]
+      - cmd: ./gradlew :stirling-pdf:copySwaggerDoc
+        platforms: [linux, darwin]
+    sources:
+      - app/core/src/main/java/**/*.java
+      - app/proprietary/src/main/java/**/*.java
+      - app/common/src/main/java/**/*.java
+    generates:
+      - SwaggerDoc.json
+
+  check:
+    desc: "Backend quality gate"
+    cmds:
+      - task: format:check
+      - task: test
+
+  version:
+    desc: "Print project version"
+    silent: true
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat printVersion --quiet" | tail -1
+        platforms: [windows]
+      - cmd: ./gradlew printVersion --quiet | tail -1
+        platforms: [linux, darwin]
+
+  licenses:check:
+    desc: "Check dependency licenses"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat checkLicense --no-parallel"
+        platforms: [windows]
+      - cmd: ./gradlew checkLicense --no-parallel
+        platforms: [linux, darwin]
+
+  licenses:generate:
+    desc: "Check and generate dependency license report"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat checkLicense generateLicenseReport --no-parallel"
+        platforms: [windows]
+      - cmd: ./gradlew checkLicense generateLicenseReport --no-parallel
+        platforms: [linux, darwin]
+
+  clean:
+    desc: "Clean build artifacts"
+    cmds:
+      - cmd: cmd /c ".\gradlew.bat clean"
+        platforms: [windows]
+      - cmd: ./gradlew clean
+        platforms: [linux, darwin]
diff --git a/.taskfiles/docker.yml b/.taskfiles/docker.yml
new file mode 100644
index 0000000..abe885a
--- /dev/null
+++ b/.taskfiles/docker.yml
@@ -0,0 +1,63 @@
+version: '3'
+
+vars:
+  COMPOSE_DIR: docker/compose
+  EMBEDDED_DIR: docker/embedded
+
+tasks:
+  build:
+    desc: "Build standard Docker image"
+    cmds:
+      - docker build -t stirling-pdf -f {{.EMBEDDED_DIR}}/Dockerfile .
+
+  build:fat:
+    desc: "Build fat Docker image (all features)"
+    cmds:
+      - docker build -t stirling-pdf-fat -f {{.EMBEDDED_DIR}}/Dockerfile.fat .
+
+  build:ultra-lite:
+    desc: "Build ultra-lite Docker image"
+    cmds:
+      - docker build -t stirling-pdf-ultra-lite -f {{.EMBEDDED_DIR}}/Dockerfile.ultra-lite .
+
+  build:frontend:
+    desc: "Build frontend-only Docker image"
+    cmds:
+      - docker build -t stirling-pdf-frontend -f docker/frontend/Dockerfile .
+
+  build:engine:
+    desc: "Build engine Docker image"
+    dir: engine
+    cmds:
+      - docker build -t stirling-pdf-engine .
+
+  up:
+    desc: "Start standard docker compose stack"
+    cmds:
+      - docker compose -f {{.COMPOSE_DIR}}/docker-compose.yml up -d
+
+  up:fat:
+    desc: "Start fat docker compose stack"
+    cmds:
+      - docker compose -f {{.COMPOSE_DIR}}/docker-compose.fat.yml up -d
+
+  up:ultra-lite:
+    desc: "Start ultra-lite docker compose stack"
+    cmds:
+      - docker compose -f {{.COMPOSE_DIR}}/docker-compose.ultra-lite.yml up -d
+
+  down:
+    desc: "Stop all running docker compose stacks"
+    cmds:
+      - docker compose -f {{.COMPOSE_DIR}}/docker-compose.yml down
+
+  logs:
+    desc: "Tail docker compose logs"
+    cmds:
+      - docker compose -f {{.COMPOSE_DIR}}/docker-compose.yml logs -f
+
+  test:
+    desc: "Run full Docker integration test suite (builds all variants and tests them)"
+    ignore_error: true
+    cmds:
+      - bash testing/test.sh {{.CLI_ARGS}}
diff --git a/.taskfiles/frontend.yml b/.taskfiles/frontend.yml
new file mode 100644
index 0000000..8c3fbc6
--- /dev/null
+++ b/.taskfiles/frontend.yml
@@ -0,0 +1,300 @@
+version: '3'
+
+# Tasks operate from the workspace root (frontend/). Editor commands pass
+# `editor` as the vite project root (positional after `build` / before the
+# mode flag) or use `--project editor/...` for tsc — so the editor lives
+# under frontend/editor/ without each task needing a cd.
+
+tasks:
+  install:
+    desc: "Install dependencies"
+    run: once
+    cmds:
+      - '{{ if eq .CI "true" }}npm ci{{ else }}npm install{{ end }}'
+    sources:
+      - package-lock.json
+      - package.json
+    status:
+      - test -d node_modules
+    env:
+      CI: '{{ .CI | default "false" }}'
+
+  prepare:env:
+    internal: true
+    run: when_changed
+    deps: [install]
+    vars:
+      MODE: '{{.MODE | default ""}}'
+    cmds:
+      - npx tsx editor/scripts/setup-env.mts{{if .MODE}} --{{.MODE}}{{end}}
+    sources:
+      - editor/scripts/setup-env.mts
+    generates:
+      - editor/.env.local
+      - editor/.env{{if .MODE}}.{{.MODE}}{{end}}.local
+
+  prepare:icons:
+    internal: true
+    run: once
+    deps: [install]
+    cmds:
+      - node editor/scripts/generate-icons.js
+
+  prepare:
+    desc: "Set up dev environment"
+    run: when_changed
+    vars:
+      MODE: '{{.MODE | default ""}}'
+    deps:
+      - task: prepare:env
+        vars: { MODE: '{{.MODE}}' }
+      - prepare:icons
+
+  # ============================================================
+  # Development
+  # ============================================================
+
+  dev:_run:
+    internal: true
+    ignore_error: true
+    vars:
+      MODE: '{{.MODE}}'
+      PORT: '{{.PORT | default "5173"}}'
+      BACKEND_URL: '{{.BACKEND_URL | default "http://localhost:8080"}}'
+      OPEN: '{{.OPEN | default ""}}'
+    env:
+      BACKEND_URL: '{{.BACKEND_URL}}'
+    cmds:
+      - npx vite editor --mode {{.MODE}} --port {{.PORT}}{{if .OPEN}} --open{{end}}
+
+  dev:
+    desc: "Start frontend dev server"
+    cmds:
+      - task: dev:proprietary
+        vars: { PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  dev:core:
+    desc: "Start frontend dev server in core mode"
+    deps: [prepare]
+    cmds:
+      - task: dev:_run
+        vars: { MODE: core, PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  dev:proprietary:
+    desc: "Start frontend dev server in proprietary mode"
+    deps: [prepare]
+    cmds:
+      - task: dev:_run
+        vars: { MODE: proprietary, PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  dev:saas:
+    desc: "Start frontend dev server in SaaS mode"
+    deps:
+      - task: prepare
+        vars: { MODE: saas }
+    cmds:
+      - task: dev:_run
+        vars: { MODE: saas, PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  dev:desktop:
+    desc: "Start frontend dev server in desktop mode"
+    deps:
+      - task: prepare
+        vars: { MODE: desktop }
+    cmds:
+      - task: dev:_run
+        vars: { MODE: desktop, PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  dev:prototypes:
+    desc: "Start frontend dev server in prototypes mode"
+    deps: [prepare]
+    cmds:
+      - task: dev:_run
+        vars: { MODE: prototypes, PORT: '{{.PORT}}', BACKEND_URL: '{{.BACKEND_URL}}', OPEN: '{{.OPEN}}' }
+
+  # ============================================================
+  # Build
+  # ============================================================
+
+  build:
+    desc: "Production build (default mode)"
+    deps: [prepare]
+    cmds:
+      - npx vite build editor
+
+  build:core:
+    desc: "Build for core mode"
+    deps: [prepare]
+    cmds:
+      - npx vite build editor --mode core
+
+  build:proprietary:
+    desc: "Build for proprietary mode"
+    deps: [prepare]
+    cmds:
+      - npx vite build editor --mode proprietary
+
+  build:saas:
+    desc: "Build for SaaS mode"
+    deps:
+      - task: prepare
+        vars: { MODE: saas }
+    cmds:
+      - npx vite build editor --mode saas
+
+  build:desktop:
+    desc: "Build for desktop mode"
+    deps:
+      - task: prepare
+        vars: { MODE: desktop }
+    cmds:
+      - npx vite build editor --mode desktop
+
+  build:prototypes:
+    desc: "Build for prototypes mode"
+    deps: [prepare]
+    cmds:
+      - npx vite build editor --mode prototypes
+
+  # ============================================================
+  # Code quality
+  # ============================================================
+
+  lint:
+    desc: "Run linting"
+    deps: [install]
+    cmds:
+      - npx eslint --max-warnings=0
+      - npx dpdm editor/src --circular --no-warning --no-tree --exit-code circular:1
+
+  lint:fix:
+    desc: "Auto-fix lint issues"
+    deps: [install]
+    cmds:
+      - npx eslint --fix
+
+  format:
+    desc: "Auto-fix code formatting"
+    deps: [install]
+    cmds:
+      - npx prettier --write .
+
+  format:check:
+    desc: "Check code formatting"
+    deps: [install]
+    cmds:
+      - npx prettier --check .
+
+  fix:
+    desc: "Auto-fix lint and format"
+    cmds:
+      - task: format
+      - task: lint:fix
+
+  typecheck:
+    desc: "Typecheck default build of the app"
+    cmds:
+      - task: typecheck:proprietary
+
+  typecheck:core:
+    desc: "Typecheck core build variant"
+    deps: [prepare]
+    cmds:
+      - npx tsc --noEmit --project editor/src/core/tsconfig.json
+
+  typecheck:proprietary:
+    desc: "Typecheck proprietary build variant"
+    deps: [prepare]
+    cmds:
+      - npx tsc --noEmit --project editor/src/proprietary/tsconfig.json
+
+  typecheck:saas:
+    desc: "Typecheck SaaS build variant"
+    deps:
+      - task: prepare
+        vars: { MODE: saas }
+    cmds:
+      - npx tsc --noEmit --project editor/src/saas/tsconfig.json
+
+  typecheck:desktop:
+    desc: "Typecheck desktop build variant"
+    deps:
+      - task: prepare
+        vars: { MODE: desktop }
+    cmds:
+      - npx tsc --noEmit --project editor/src/desktop/tsconfig.json
+
+  typecheck:scripts:
+    desc: "Typecheck scripts"
+    deps: [prepare]
+    cmds:
+      - npx tsc --noEmit --project editor/scripts/tsconfig.json
+
+  typecheck:prototypes:
+    desc: "Typecheck prototypes build variant"
+    deps: [prepare]
+    cmds:
+      - npx tsc --noEmit --project editor/src/prototypes/tsconfig.json
+
+  typecheck:all:
+    desc: "Typecheck all build variants"
+    cmds:
+      - task: typecheck:core
+      - task: typecheck:proprietary
+      - task: typecheck:saas
+      - task: typecheck:desktop
+      - task: typecheck:scripts
+      - task: typecheck:prototypes
+
+  # ============================================================
+  # Quality Gate
+  # ============================================================
+
+  check:
+    desc: "Quick quality gate for local development"
+    cmds:
+      - task: typecheck
+      - task: lint
+      - task: format:check
+      - task: test
+
+  check:all:
+    desc: "Full CI quality gate"
+    cmds:
+      - task: typecheck:all
+      - task: lint
+      - task: format:check
+      - task: build
+      - task: test
+
+  # ============================================================
+  # Test
+  # ============================================================
+
+  test:
+    desc: "Run tests"
+    deps: [install]
+    cmds:
+      - npx vitest run --root editor
+
+  test:watch:
+    desc: "Run tests in watch mode"
+    deps: [install]
+    cmds:
+      - npx vitest --watch --root editor
+
+  test:coverage:
+    desc: "Run tests with coverage"
+    deps: [install]
+    cmds:
+      - npx vitest --coverage --root editor
+
+  # ============================================================
+  # Code Generation
+  # ============================================================
+
+  licenses:generate:
+    desc: "Generate frontend license report"
+    deps: [install]
+    cmds:
+      - node editor/scripts/generate-licenses.js
diff --git a/DATABASE.md b/DATABASE.md
new file mode 100644
index 0000000..5c245af
--- /dev/null
+++ b/DATABASE.md
@@ -0,0 +1,34 @@
+# New Database Backup and Import Functionality
+
+## Functionality Overview
+
+The newly introduced feature enhances the application with robust database backup and import capabilities. This feature is designed to ensure data integrity and provide a straightforward way to manage database backups. Here's how it works:
+
+1. Automatic Backup Creation
+   - The system automatically creates a database backup on a configurable schedule (default: daily at midnight via `system.databaseBackup.cron`). This ensures that there is always a recent backup available, minimizing the risk of data loss.
+2. Manual Backup Export
+   - Admin actions that modify the user database trigger a manual export of the database. This keeps the backup up-to-date with the latest changes and provides an extra layer of data security.
+3. Importing Database Backups
+   - Admin users can import a database backup either via the web interface or API endpoints. This allows for easy restoration of the database to a previous state in case of data corruption or other issues.
+   - The import process ensures that the database structure and data are correctly restored, maintaining the integrity of the application.
+4. Managing Backup Files
+   - Admins can view a list of all existing backup files, along with their creation dates and sizes. This helps in managing storage and identifying the most recent or relevant backups.
+   - Backup files can be downloaded for offline storage or transferred to other environments, providing flexibility in database management.
+   - Unnecessary backup files can be deleted through the interface to free up storage space and maintain an organized backup directory.
+
+## User Interface
+
+### Web Interface
+
+1. Upload SQL files to import database backups.
+2. View details of existing backups, such as file names, creation dates, and sizes.
+3. Download backup files for offline storage.
+4. Delete outdated or unnecessary backup files.
+
+### API Endpoints
+
+1. Import database backups by uploading SQL files.
+2. Download backup files.
+3. Delete backup files.
+
+This new functionality streamlines database management, ensuring that backups are always available and easy to manage, thus improving the reliability and resilience of the application.
diff --git a/FILE_SHARING.md b/FILE_SHARING.md
new file mode 100644
index 0000000..e0d96cf
--- /dev/null
+++ b/FILE_SHARING.md
@@ -0,0 +1,444 @@
+# File Sharing Feature - Architecture & Workflow
+
+## Overview
+
+The File Sharing feature enables users to store files server-side and share them with other registered users or via token-based share links. Files are stored using a pluggable storage provider (local filesystem or database) with optional quota enforcement.
+
+**Key Capabilities:**
+- Server-side file storage (upload, update, download, delete)
+- Optional history bundle and audit log attachments per file
+- Direct user-to-user sharing with access roles
+- Token-based share links (requires `system.frontendUrl`)
+- Optional email notifications for shares (requires `mail.enabled`)
+- Access audit trail (tracks who accessed a share link and how)
+- Automatic share link expiration
+- Storage quotas (per-user and total)
+- Pluggable storage backend (local filesystem or database BLOB)
+- Integration with the Shared Signing workflow
+
+## Architecture
+
+### Database Schema
+
+**`stored_files`**
+- One record per uploaded file
+- Stores file metadata (name, content type, size, storage key)
+- Optionally links to a history bundle and audit log as separate stored objects
+- `workflow_session_id` — nullable link to a `WorkflowSession` (signing feature)
+- `file_purpose` — enum classifying the file's role: `GENERIC`, `SIGNING_ORIGINAL`, `SIGNING_SIGNED`, `SIGNING_HISTORY`
+
+**`file_shares`**
+- One record per sharing relationship
+- Two share types, distinguished by which fields are set:
+  - **User share**: `shared_with_user_id` is set, `share_token` is null
+  - **Link share**: `share_token` is set (UUID), `shared_with_user_id` is null
+- `access_role` — `EDITOR`, `COMMENTER`, or `VIEWER`
+- `expires_at` — nullable expiration for link shares
+- `workflow_participant_id` — when set, marks this as a **workflow share** (hidden from the file manager, accessible only via workflow endpoints)
+
+**`file_share_accesses`**
+- One record per access event on a share link
+- Tracks: user, share link, access type (`VIEW` or `DOWNLOAD`), timestamp
+
+**`storage_cleanup_entries`**
+- Queue of storage keys to be deleted asynchronously
+- Used when a file is deleted but the physical storage object cleanup is deferred
+
+### Access Roles
+
+| Role | Can Read | Can Write |
+|------|----------|-----------|
+| `EDITOR` | ✅ | ✅ |
+| `COMMENTER` | ✅ | ❌ |
+| `VIEWER` | ✅ | ❌ |
+
+Default role when none is specified: `EDITOR`.
+
+Owners always have full access regardless of role.
+
+#### Role Semantics: COMMENTER vs VIEWER
+
+In the file storage layer, `COMMENTER` and `VIEWER` are equivalent — both grant read-only access and neither can replace file content. The distinction is meaningful in the **signing workflow** context:
+
+| Context | COMMENTER | VIEWER |
+|---------|-----------|--------|
+| File storage | Read only (same as VIEWER) | Read only |
+| Signing workflow | Can submit a signing action | Read only |
+
+`WorkflowParticipant.canEdit()` returns `true` for `COMMENTER` (and `EDITOR`) roles, which the signing workflow uses to determine if a participant can still submit a signature. Once a participant has signed or declined, their effective role is automatically downgraded to `VIEWER` regardless of their configured role.
+
+The rationale: "annotating" a document (submitting a signature) is not the same as "replacing" it. COMMENTER grants annotation rights without file-replacement rights.
+
+### Backend Architecture
+
+#### Service Layer
+
+**FileStorageService** (`1137 lines`)
+- Core file management service
+- Upload, update, download, and delete operations
+- User share management (share, revoke, leave)
+- Link share management (create, revoke, access)
+- Access recording and listing
+- Storage quota enforcement
+- Configuration feature gate checks
+
+**StorageCleanupService**
+- Scheduled daily: deletes orphaned storage keys from `storage_cleanup_entries`
+- Scheduled daily: purges expired share links from `file_shares`
+- Processes cleanup in batches of 50 entries
+
+#### Storage Providers
+
+**LocalStorageProvider**
+- Files stored on the filesystem under `storage.local.basePath` (default: `./storage`)
+- Storage key is a path relative to the base directory
+
+**DatabaseStorageProvider**
+- Files stored as BLOBs in `stored_file_blobs` table
+- No filesystem dependency
+
+Provider is selected at startup via `storage.provider: local | database`.
+
+#### Controller Layer
+
+**FileStorageController** (`/api/v1/storage`)
+- All endpoints require authentication
+- File CRUD and sharing operations
+
+### Data Flow
+
+```
+User uploads file → StorageProvider stores bytes → StoredFile record created
+       ↓
+Owner shares file → FileShare record created (user or link)
+       ↓
+Recipient accesses file → Access recorded → File bytes streamed
+```
+
+## File Operations
+
+### Upload File
+
+```bash
+POST /api/v1/storage/files
+Content-Type: multipart/form-data
+
+file: document.pdf                # Required — main file
+historyBundle: history.json       # Optional — version history
+auditLog: audit.json              # Optional — audit trail
+```
+
+**Response:**
+```json
+{
+  "id": 42,
+  "fileName": "document.pdf",
+  "contentType": "application/pdf",
+  "sizeBytes": 102400,
+  "owner": "alice",
+  "ownedByCurrentUser": true,
+  "accessRole": "editor",
+  "createdAt": "2025-01-01T12:00:00",
+  "updatedAt": "2025-01-01T12:00:00",
+  "sharedWithUsers": [],
+  "sharedUsers": [],
+  "shareLinks": []
+}
+```
+
+### Update File
+
+Replaces the file content. Only the owner can update.
+
+```bash
+PUT /api/v1/storage/files/{fileId}
+Content-Type: multipart/form-data
+
+file: document_v2.pdf
+historyBundle: history.json       # Optional
+auditLog: audit.json              # Optional
+```
+
+### List Files
+
+Returns all files owned by or shared with the current user. Workflow-shared files (signing participants) are excluded — those are accessible via signing endpoints only.
+
+```bash
+GET /api/v1/storage/files
+```
+
+Response is sorted by `createdAt` descending.
+
+### Download File
+
+```bash
+GET /api/v1/storage/files/{fileId}/download?inline=false
+```
+
+- `inline=false` (default) — `Content-Disposition: attachment`
+- `inline=true` — `Content-Disposition: inline` (for browser preview)
+
+### Delete File
+
+Only the owner can delete. All associated share links and their access records are deleted first, then the database record, then the physical storage object.
+
+```bash
+DELETE /api/v1/storage/files/{fileId}
+```
+
+## Sharing Operations
+
+### Share with User
+
+```bash
+POST /api/v1/storage/files/{fileId}/shares/users
+Content-Type: application/json
+
+{
+  "username": "bob",          # Username or email address
+  "accessRole": "editor"      # "editor", "commenter", or "viewer" (default: "editor")
+}
+```
+
+**Behaviour:**
+- If the target user exists: creates/updates a `FileShare` with `sharedWithUser` set
+- If `username` is an email address and the user doesn't exist: creates a share link and sends a notification email (requires `sharing.emailEnabled` and `sharing.linkEnabled`)
+- If the target user is the owner: returns 400
+- If sharing is disabled: returns 403
+
+### Revoke User Share
+
+Only the owner can revoke.
+
+```bash
+DELETE /api/v1/storage/files/{fileId}/shares/users/{username}
+```
+
+### Leave Shared File
+
+The recipient removes themselves from a shared file.
+
+```bash
+DELETE /api/v1/storage/files/{fileId}/shares/self
+```
+
+### Create Share Link
+
+Creates a token-based link for anonymous/authenticated access. Requires `sharing.linkEnabled` and `system.frontendUrl` to be configured.
+
+```bash
+POST /api/v1/storage/files/{fileId}/shares/links
+Content-Type: application/json
+
+{
+  "accessRole": "viewer"      # Optional (default: "editor")
+}
+```
+
+**Response:**
+```json
+{
+  "token": "550e8400-e29b-41d4-a716-446655440000",
+  "accessRole": "viewer",
+  "createdAt": "2025-01-01T12:00:00",
+  "expiresAt": "2025-01-04T12:00:00"
+}
+```
+
+Expiration is set to `now + sharing.linkExpirationDays` (default: 3 days).
+
+### Revoke Share Link
+
+```bash
+DELETE /api/v1/storage/files/{fileId}/shares/links/{token}
+```
+
+Also deletes all access records for that token.
+
+## Share Link Access
+
+### Download via Share Link
+
+Authentication is required (even for share links). Anonymous access is not permitted.
+
+```bash
+GET /api/v1/storage/share-links/{token}?inline=false
+```
+
+- Returns 401 if unauthenticated
+- Returns 403 if authenticated but link doesn't permit access
+- Returns 410 if the link has expired
+- Records a `FileShareAccess` entry on success
+
+> **Token-as-credential semantics:** Any authenticated user who holds the token can access the file — the token is the credential. If you need per-user access control (only a specific person can open it), use "Share with User" instead. Share links are appropriate for broader distribution where possession of the token implies authorization.
+
+### Get Share Link Metadata
+
+```bash
+GET /api/v1/storage/share-links/{token}/metadata
+```
+
+Returns file name, owner, access role, creation/expiry timestamps, and whether the current user owns the file.
+
+### List Accessed Share Links
+
+Returns the most recent access for each non-expired share link the current user has accessed.
+
+```bash
+GET /api/v1/storage/share-links/accessed
+```
+
+### List Accesses for a Link (Owner Only)
+
+```bash
+GET /api/v1/storage/files/{fileId}/shares/links/{token}/accesses
+```
+
+Returns per-user access history (username, VIEW/DOWNLOAD, timestamp), sorted descending by time.
+
+## Workflow Share Integration
+
+Signing workflow participants access documents via their own `WorkflowParticipant.shareToken`. No `FileShare` record is created for participants; access control is self-contained in the `WorkflowParticipant` entity.
+
+The `FileShare.workflow_participant_id` column and the `FileShare.isWorkflowShare()` method are **deprecated**. Legacy data (sessions created before this change) may still have `FileShare` records with `workflow_participant_id` set, which continue to work via the existing token lookup path in `UnifiedAccessControlService`. No new records are created.
+
+`GET /api/v1/storage/files` returns all files owned by or shared with the current user (via `FileShare`). Signing-session PDFs use the `file_purpose` field (`SIGNING_ORIGINAL`, `SIGNING_SIGNED`, etc.) to distinguish them from generic files. The file manager UI can filter on this field if needed.
+
+## API Reference
+
+| Method | Endpoint | Description | Auth |
+|--------|----------|-------------|------|
+| POST | `/api/v1/storage/files` | Upload file | Required |
+| PUT | `/api/v1/storage/files/{id}` | Update file | Required (owner) |
+| GET | `/api/v1/storage/files` | List accessible files | Required |
+| GET | `/api/v1/storage/files/{id}` | Get file metadata | Required |
+| GET | `/api/v1/storage/files/{id}/download` | Download file | Required |
+| DELETE | `/api/v1/storage/files/{id}` | Delete file | Required (owner) |
+| POST | `/api/v1/storage/files/{id}/shares/users` | Share with user | Required (owner) |
+| DELETE | `/api/v1/storage/files/{id}/shares/users/{username}` | Revoke user share | Required (owner) |
+| DELETE | `/api/v1/storage/files/{id}/shares/self` | Leave shared file | Required |
+| POST | `/api/v1/storage/files/{id}/shares/links` | Create share link | Required (owner) |
+| DELETE | `/api/v1/storage/files/{id}/shares/links/{token}` | Revoke share link | Required (owner) |
+| GET | `/api/v1/storage/share-links/{token}` | Download via share link | Required |
+| GET | `/api/v1/storage/share-links/{token}/metadata` | Get share link metadata | Required |
+| GET | `/api/v1/storage/share-links/accessed` | List accessed share links | Required |
+| GET | `/api/v1/storage/files/{id}/shares/links/{token}/accesses` | List share accesses | Required (owner) |
+
+## Configuration
+
+All storage settings live under the `storage:` key in `settings.yml`:
+
+```yaml
+storage:
+  enabled: true                  # Requires security.enableLogin = true
+  provider: local                # 'local' or 'database'
+  local:
+    basePath: './storage'        # Filesystem base directory (local provider only)
+  quotas:
+    maxStorageMbPerUser: -1      # Per-user storage cap in MB; -1 = unlimited
+    maxStorageMbTotal: -1        # Total storage cap in MB; -1 = unlimited
+    maxFileMb: -1                # Max size per upload (main + history + audit) in MB; -1 = unlimited
+  sharing:
+    enabled: false               # Master switch for all sharing (opt-in)
+    linkEnabled: false           # Enable token-based share links (requires system.frontendUrl)
+    emailEnabled: false          # Enable email notifications (requires mail.enabled)
+    linkExpirationDays: 3        # Days until share links expire
+```
+
+**Prerequisites:**
+- `storage.enabled` requires `security.enableLogin = true`
+- `sharing.linkEnabled` requires `system.frontendUrl` to be set (used to build share link URLs)
+- `sharing.emailEnabled` requires `mail.enabled = true`
+
+## Security Considerations
+
+### Access Control
+- All endpoints require authentication — there is no anonymous access
+- Owner-only operations enforced in service layer (not just controller)
+- `requireReadAccess` / `requireEditorAccess` checked on every download
+
+### Share Link Security
+- Tokens are UUIDs (random, not guessable)
+- Expiration enforced on every access
+- Expired links return HTTP 410 Gone
+- Revoked links delete all access records
+
+### Quota Enforcement
+- Checked before storing (not after)
+- Accounts for existing file size when replacing (only the delta counts)
+- Covers main file + history bundle + audit log in a single check
+
+## Automatic Cleanup
+
+`StorageCleanupService` runs two scheduled jobs daily:
+
+1. **Orphaned storage cleanup** — processes up to 50 `StorageCleanupEntry` records, deletes the physical storage object, then removes the entry. Failed attempts increment `attemptCount` for retry.
+
+2. **Expired share link cleanup** — deletes all `FileShare` records where `expiresAt` is in the past and `shareToken` is set.
+
+## Troubleshooting
+
+**"Storage is disabled":**
+- Check `storage.enabled: true` in settings
+- Verify `security.enableLogin: true`
+
+**"Share links are disabled":**
+- Check `sharing.linkEnabled: true`
+- Verify `system.frontendUrl` is set and non-empty
+
+**"Email sharing is disabled":**
+- Check `sharing.emailEnabled: true`
+- Verify `mail.enabled: true` and mail configuration
+
+**Signing-session PDF appearing in the general file list:**
+- This is expected — signing PDFs are accessible to owners and shared users
+- Filter by `file_purpose` (`SIGNING_ORIGINAL`, `SIGNING_SIGNED`) in the UI to distinguish them
+
+**Share link returns 410:**
+- Link has expired — check `expires_at` in `file_shares` table
+- Owner must create a new link
+
+### Debug Queries
+
+```sql
+-- List files and their share counts
+SELECT sf.stored_file_id, sf.original_filename, u.username as owner,
+       COUNT(DISTINCT fs.file_share_id) FILTER (WHERE fs.shared_with_user_id IS NOT NULL) as user_shares,
+       COUNT(DISTINCT fs.file_share_id) FILTER (WHERE fs.share_token IS NOT NULL) as link_shares
+FROM stored_files sf
+LEFT JOIN users u ON sf.owner_id = u.user_id
+LEFT JOIN file_shares fs ON fs.stored_file_id = sf.stored_file_id
+GROUP BY sf.stored_file_id, u.username;
+
+-- Check share link expiration
+SELECT share_token, access_role, created_at, expires_at,
+       expires_at < NOW() as is_expired
+FROM file_shares
+WHERE share_token IS NOT NULL;
+
+-- Check access history for a share link
+SELECT u.username, fsa.access_type, fsa.accessed_at
+FROM file_share_accesses fsa
+JOIN file_shares fs ON fsa.file_share_id = fs.file_share_id
+JOIN users u ON fsa.user_id = u.user_id
+WHERE fs.share_token = '{token}'
+ORDER BY fsa.accessed_at DESC;
+
+-- Pending cleanup entries
+SELECT storage_key, attempt_count, updated_at
+FROM storage_cleanup_entries
+ORDER BY updated_at ASC;
+```
+
+## Summary
+
+The File Sharing feature provides:
+- ✅ Server-side file storage with pluggable backend (local/database)
+- ✅ History bundle and audit log attachments per file
+- ✅ Direct user-to-user sharing with EDITOR/COMMENTER/VIEWER roles
+- ✅ Token-based share links with expiration
+- ✅ Optional email notifications for shares
+- ✅ Per-access audit trail for share links
+- ✅ Storage quotas (per-user, total, per-file)
+- ✅ Automatic cleanup of expired links and orphaned storage
+- ✅ Workflow integration (signing-session PDFs stored via same infrastructure; participant access via `WorkflowParticipant.shareToken`)
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..9fd69f2
--- /dev/null
+++ b/README.md
@@ -0,0 +1,228 @@
+# Stirling-PDF
+
+## 基本信息
+
+| 项目 | 内容 |
+|------|------|
+| **GitHub** | https://github.com/Stirling-Tools/Stirling-PDF |
+| **Stars** | **79,420** ⭐ (#1 PDF Application on GitHub) |
+| **描述** | 随时随地编辑PDF的开源PDF编辑平台 |
+| **技术栈** | Java/Spring Boot + Python AI Engine + React |
+| **许可证** | Open-core |
+
+## 核心功能
+
+### 50+ PDF工具
+- **编辑**: 合并、分割、旋转、裁剪
+- **安全**: 签名、编辑、密码保护
+- **转换**: PDF与Word/Excel/图片互转
+- **OCR**: 文字识别
+- **压缩**: 优化PDF大小
+- **自动化**: 无代码工作流 + REST API
+
+### 部署方式
+- **桌面客户端**: Tauri跨平台桌面应用
+- **浏览器UI**: React SPA
+- **Docker**: `docker run -p 8080:8080 docker.stirlingpdf.com/stirlingtools/stirling-pdf`
+- **Kubernetes**: Helm charts支持
+
+### 企业级功能
+- **SSO**: 单点登录
+- **审计**: 操作审计日志
+- **私有API**: REST API for 几乎所有工具
+- **40+语言**: 国际化支持
+
+## 技术架构
+
+### 三组件分离设计
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                     Stirling-PDF                             │
+├─────────────────────────────────────────────────────────────┤
+│  Frontend (React SPA)                                       │
+│  - React + TypeScript + Vite                                │
+│  - Mantine UI + TailwindCSS                                │
+│  - PDF.js (客户端渲染)                                      │
+│  - IndexedDB (本地存储)                                     │
+├─────────────────────────────────────────────────────────────┤
+│  Backend (Java Spring Boot)                                 │
+│  - JDK 25                                                   │
+│  - PDFBox (PDF操作)                                         │
+│  - LibreOffice (文档转换)                                   │
+│  - qpdf (PDF优化)                                           │
+│  - Spring Security (可选)                                  │
+├─────────────────────────────────────────────────────────────┤
+│  Engine (Python FastAPI)                                    │
+│  - AI推理服务                                               │
+│  - 任务规划和解译                                           │
+│  - 不持有持久状态                                           │
+└─────────────────────────────────────────────────────────────┘
+```
+
+### 技术栈
+
+| 组件 | 技术 |
+|------|------|
+| **Backend** | Spring Boot (JDK 25), PDFBox, LibreOffice, qpdf, Lombok |
+| **Frontend** | React, TypeScript, Vite, Mantine, TailwindCSS, PDF.js, i18next |
+| **Engine** | Python FastAPI |
+| **Desktop** | Tauri (Rust) |
+| **Infrastructure** | Docker, Gradle |
+
+### 目录结构
+
+```
+Stirling-PDF/
+├── app/
+│   ├── common/          # 公共代码
+│   ├── core/            # 核心PDF操作
+│   ├── proprietary/     # 专有功能(企业版)
+│   └── saas/            # SaaS功能
+├── frontend/            # React前端
+├── engine/              # Python AI引擎
+├── docker/              # Docker构建
+├── gradle/              # Gradle构建
+└── Taskfile.yml         # 统一命令
+```
+
+## Taskfile 统一命令系统
+
+项目使用 [Task](https://taskfile.dev/) 作为统一命令运行器：
+
+### 快速参考
+
+| 命令 | 功能 |
+|------|------|
+| `task install` | 安装所有依赖 |
+| `task dev` | 启动后端+前端 |
+| `task dev:all` | 启动后端+前端+引擎 |
+| `task build` | 构建所有组件 |
+| `task test` | 运行所有测试 |
+| `task lint` | 运行所有linter |
+| `task format` | 自动修复格式 |
+| `task check` | 完整质量检查 |
+| `task docker:build` | 构建Docker镜像 |
+| `task docker:up` | 启动Docker compose |
+
+### Docker变体
+
+- **standard**: 标准版本
+- **fat**: 包含所有依赖
+- **ultra-lite**: 精简版
+
+## 项目亮点
+
+### 1. Taskfile 统一命令
+所有构建/开发/测试命令统一管理，跨平台一致体验。
+
+### 2. 三组件分离架构
+- Java后端: 核心业务逻辑
+- Python Engine: AI推理
+- 前端: 用户界面
+
+### 3. 企业级功能设计
+- SSO单点登录
+- 操作审计
+- 完整REST API
+
+### 4. Open-core 商业模式
+- 核心开源
+- 企业版付费功能
+
+### 5. 完善的国际化
+- 40+语言支持
+- 完善的翻译指南
+
+### 6. 安全设计
+- 私有化部署
+- 不上传外部服务
+- 安全模式开发
+
+## 开发环境
+
+### 前置要求
+- [Task](https://taskfile.dev/installation/)
+- Docker
+- Git
+- Java JDK 25
+- Node.js 18+
+- Gradle 7.0+
+- Python + uv (for engine)
+
+### 快速开始
+
+```bash
+# 克隆项目
+git clone https://github.com/Stirling-Tools/Stirling-PDF.git
+cd Stirling-PDF
+
+# 安装依赖
+task install
+
+# 启动开发
+task dev
+
+# 运行测试
+task test
+
+# 质量检查
+task check
+```
+
+## 添加新工具
+
+### 目录结构
+```
+frontend/editor/src/
+├── hooks/tools/[toolName]/
+│   ├── use[ToolName]Parameters.ts     # 参数定义
+│   └── use[ToolName]Operation.ts      # 操作逻辑
+├── components/tools/[toolName]/
+│   └── [ToolName]Settings.tsx         # 设置UI
+└── tools/
+    └── [ToolName].tsx                 # 主组件
+```
+
+### 核心模式
+```typescript
+// 使用 useBaseTool 简化hook管理
+export const use[ToolName]Parameters = () => {
+  return useBaseParameters({
+    defaultParameters,
+    endpointName: 'your-endpoint-name',
+  });
+};
+
+// 使用 useToolOperation 处理操作
+export const use[ToolName]Operation = () => {
+  return useToolOperation({
+    toolType: ToolType.singleFile,
+    buildFormData: build[ToolName]FormData,
+    endpoint: '/api/v1/category/endpoint-name',
+  });
+};
+```
+
+## 相关项目
+
+- [Stirling-PDF-chart](https://github.com/Stirling-Tools/Stirling-PDF-chart) - Helm charts
+- [Stirling-PDF-Enterprise-and-Login](https://github.com/Stirling-Tools/Stirling-PDF-Enterprise-and-Login) - 企业版
+- [stirling_pdf_addon](https://github.com/pablodelarco/stirling_pdf_addon) - 插件
+
+---
+
+## 研究笔记
+
+**注意**: 由于GitHub下载超时，此仓库仅包含从API获取的文档信息。
+
+**研究日期**: 2026-05-25
+**Stars**: 79,420
+**建议**: 高价值项目，架构设计值得学习
+
+**借鉴价值**:
+- ⭐⭐⭐⭐⭐ Taskfile统一命令系统
+- ⭐⭐⭐⭐⭐ 三组件分离架构
+- ⭐⭐⭐⭐⭐ 企业功能(SSO/审计/API)
+- ⭐⭐⭐⭐ Python Engine模式
+- ⭐⭐⭐⭐ 多语言国际化
\ No newline at end of file
diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 0000000..5f532aa
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,63 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+The Stirling-PDF team takes security vulnerabilities seriously. We appreciate your efforts to responsibly disclose your findings.
+
+### How to Report
+
+You can report security vulnerabilities through two channels:
+
+1. **GitHub Security Advisory**:
+   - Navigate to the [Security tab](https://github.com/Stirling-Tools/Stirling-PDF/security) in our repository
+   - Click on "Report a vulnerability"
+   - Provide a detailed description of the vulnerability
+
+2. **Direct Email**:
+   - Send your report to security@stirlingpdf.com
+   - Please include as much information as possible about the vulnerability
+
+### What to Include
+
+When reporting a vulnerability, please provide:
+
+- A clear description of the vulnerability
+- Steps to reproduce the issue
+- Any potential impact
+- If possible, suggestions for addressing the vulnerability
+- Your contact information for follow-up questions
+
+### Response Time
+
+We aim to acknowledge receipt of your vulnerability report within 48 hours
+
+### Process
+
+1. Submit your report through one of the channels above
+2. Receive an acknowledgment from our team
+3. Our team will investigate and validate the issue
+4. We will work on a fix and keep you updated on our progress
+5. Once resolved, we will publish the fix and acknowledge your contribution (if desired)
+
+### Bug Bounty
+
+At this time, we do not offer a bug bounty program. However, we greatly appreciate your efforts in making Stirling-PDF more secure and will acknowledge your contribution in our release notes (unless you prefer to remain anonymous).
+
+## Supported Versions
+
+Only the latest version of Stirling-PDF is supported for security updates. We do not backport security fixes to older versions.
+
+| Version | Supported          |
+| ------- | ------------------ |
+| Latest  | :white_check_mark: |
+| Older   | :x:               |
+
+**Please note:** Before reporting a security issue, ensure you are using the latest version of Stirling-PDF. Security reports for older versions will not be accepted.
+
+## Security Best Practices
+
+When deploying Stirling-PDF:
+
+1. Always use the latest version
+2. Follow our deployment guidelines
+3. Regularly check for and apply updates