Fix/disable table comment for unsupported db (#518)

* fix(structure-editor): disable table comment input for databases that don't support comments (e.g. SQLite)

## 背景说明
SQLite 不支持表注释（COMMENT），但表注释输入框始终可编辑。用户修改注释后，SQL 预览显示暂无变更且应用变更按钮不可用，造成困惑的 UX。

## 修改内容
- 新增 isTableCommentDisabled 计算属性，基于 structureCapabilities.comment 控制禁用状态
- 表注释 Input 添加 :disabled 绑定，禁用时输入框变灰不可编辑
- 禁用时在输入框右侧显示 Info 图标，hover 显示 Tooltip 说明
- 三语言（zh-CN / en / es）新增 tableCommentUnsupported 翻译

## 影响范围
- SQLite、DuckDB 及未知数据库类型：输入框被禁用 + Tooltip 提示
- MySQL、PostgreSQL、ClickHouse 等支持注释的数据库：完全不受影响
- 后端 generate_comment_ddl 已有对等过滤（仅 Postgres/Oracle/ClickHouse 生成 COMMENT SQL）

## 测试
- 建议补充：dbType 为 sqlite 时 isTableCommentDisabled 为 true 的单元测试

* test(structure-editor): add tests for table comment disabled state and unsupported DB capabilities

apps/desktop/src/components/structure/TableStructureEditor.vue

@@ -12,6 +12,7 @@ import {
   ChevronDown,
   ChevronUp,
   Database,
+  Info,
   KeyRound,
   Loader2,
   Maximize2,
@@ -28,6 +29,7 @@ import {
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
+import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
 import { SearchableSelect } from "@/components/ui/searchable-select";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { useConnectionStore } from "@/stores/connectionStore";
@@ -134,6 +136,7 @@ function onIndexColResize(e: MouseEvent, col: number) {
 const connection = computed(() => (props.connectionId ? store.getConfig(props.connectionId) : undefined));
 const databaseType = computed(() => connection.value?.db_type);
 const structureCapabilities = computed(() => getTableStructureCapabilities(databaseType.value));
+const isTableCommentDisabled = computed(() => !structureCapabilities.value.comment);
 const dataTypeOptions = computed(() => DATA_TYPE_OPTIONS[databaseType.value ?? ""] ?? []);
 
 const indexTypesByDb: Record<string, string[]> = {
@@ -509,7 +512,14 @@ watch(
         v-model="tableComment"
         :placeholder="t('structureEditor.tableCommentPlaceholder')"
         class="h-6 max-w-[320px] text-[11px]"
+        :disabled="isTableCommentDisabled"
       />
+      <Tooltip v-if="isTableCommentDisabled">
+        <TooltipTrigger as-child>
+          <Info class="h-4 w-4 shrink-0 text-muted-foreground" />
+        </TooltipTrigger>
+        <TooltipContent>{{ t("structureEditor.tableCommentUnsupported") }}</TooltipContent>
+      </Tooltip>
     </div>
 
     <div v-if="loading" class="flex min-h-0 flex-1 items-center justify-center gap-2 text-sm text-muted-foreground">

apps/desktop/src/i18n/locales/en.ts

@@ -989,6 +989,7 @@ export default {
     editComment: "Edit comment",
     commentPlaceholder: "Enter column comment...",
     tableCommentPlaceholder: "Enter table comment...",
+    tableCommentUnsupported: "Table comments are not supported by this database",
     actions: "Actions",
     indexName: "Index",
     indexColumns: "Columns",

apps/desktop/src/i18n/locales/es.ts

@@ -883,6 +883,7 @@ export default {
     editComment: "Editar comentario",
     commentPlaceholder: "Ingresar comentario de columna...",
     tableCommentPlaceholder: "Ingresar comentario de tabla...",
+    tableCommentUnsupported: "La base de datos no admite comentarios de tabla",
     actions: "Acciones",
     indexName: "Índice",
     indexColumns: "Columnas",

apps/desktop/src/i18n/locales/zh-CN.ts

@@ -967,6 +967,7 @@ export default {
     editComment: "编辑注释",
     commentPlaceholder: "输入字段注释...",
     tableCommentPlaceholder: "输入表注释...",
+    tableCommentUnsupported: "当前数据库不支持表注释",
     actions: "操作",
     indexName: "索引名",
     indexColumns: "字段列表",

packages/app-tests/tableStructureCapabilities.test.ts

@@ -5,6 +5,14 @@ import {
   getTableStructureCapabilities,
 } from "../../apps/desktop/src/lib/tableStructureCapabilities.ts";
 
+test("sqlite and duckdb do not support table comments", () => {
+  for (const dbType of ["sqlite", "duckdb"] as const) {
+    const caps = getTableStructureCapabilities(dbType);
+    assert.equal(caps.comment, false, `${dbType} should not support comments`);
+    assert.equal(caps.createTable, true, `${dbType} should still support creating tables`);
+  }
+});
+
 test("postgres-like databases expose safe structure editing capabilities", () => {
   for (const dbType of ["postgres", "gaussdb", "opengauss", "highgo", "vastbase", "kingbase"] as const) {
     const caps = getTableStructureCapabilities(dbType);

packages/app-tests/tableStructureEditorPresentation.test.ts

@@ -80,3 +80,11 @@ test("new column input is focused after adding a field", () => {
   assert.match(source, /data-column-name-input/);
   assert.match(source, /input\?\.focus\(\)/);
 });
+
+test("table comment input is disabled and shows tooltip when database does not support comments", () => {
+  assert.match(source, /isTableCommentDisabled/);
+  assert.match(source, /:disabled="isTableCommentDisabled"/);
+  assert.match(source, /v-if="isTableCommentDisabled"/);
+  assert.match(source, /Tooltip/);
+  assert.match(source, /tableCommentUnsupported/);
+});