perf: bound amp hook post queue

Summary:
- replace the generated Amp plugin unbounded promise-chain POST queue with a bounded async queue
- keep hook callbacks non-blocking while capping retained status payloads during Orca downtime
- update installer source assertions for bounded backlog behavior

Validation:
- pnpm exec vitest run src/main/amp/hook-service.test.ts src/main/agent-hooks/remote-hook-service-installers.test.ts src/main/agent-trust-presets.test.ts src/main/antigravity/hook-service.test.ts src/main/attribution/terminal-attribution.test.ts
- pnpm run typecheck:node
- pnpm lint
- git diff --check
- GitHub CI verify + track-community-pr passed

src/main/amp/hook-service.test.ts

@@ -50,10 +50,13 @@ describe('AmpHookService', () => {
     expect(source).toContain("amp.on('tool.result'")
     expect(source).toContain("amp.on('agent.end'")
     expect(source).toContain('return { action: "allow" }')
-    expect(source).toContain('let postQueue = Promise.resolve()')
+    expect(source).toContain('const MAX_PENDING_POSTS = 50')
+    expect(source).toContain('let postQueue: QueuedPost[] = []')
     expect(source).toContain('function enqueuePost')
+    expect(source).toContain('postQueue.shift()')
     expect(source).toContain('enqueuePost("tool.call"')
     expect(source).not.toContain('await post("tool.call"')
+    expect(source).not.toContain('postQueue = postQueue.then')
     expect(source).toContain('process.env.ORCA_PANE_KEY')
     expect(source).toContain('process.env.ORCA_AGENT_HOOK_ENDPOINT')
   })

src/main/amp/hook-service.ts

@@ -247,11 +247,35 @@ function getAmpPluginSource(): string {
     '  }',
     '}',
     '',
-    'let postQueue = Promise.resolve()',
+    'const MAX_PENDING_POSTS = 50',
+    'type QueuedPost = { hookEventName: string; payload: Record<string, unknown> }',
+    'let postQueue: QueuedPost[] = []',
+    'let postDraining = false',
+    '',
+    'async function drainPostQueue(): Promise<void> {',
+    '  if (postDraining) return',
+    '  postDraining = true',
+    '  try {',
+    '    while (postQueue.length > 0) {',
+    '      const next = postQueue.shift()',
+    '      if (!next) continue',
+    '      await post(next.hookEventName, next.payload)',
+    '    }',
+    '  } finally {',
+    '    postDraining = false',
+    '    if (postQueue.length > 0) {',
+    '      void drainPostQueue()',
+    '    }',
+    '  }',
+    '}',
     'function enqueuePost(hookEventName: string, payload: Record<string, unknown>): void {',
-    '  // Why: keep hook callbacks non-blocking while preserving Amp event order.',
-    '  postQueue = postQueue.then(() => post(hookEventName, payload), () => post(hookEventName, payload))',
-    '  void postQueue.catch(() => {})',
+    '  // Why: keep hook callbacks non-blocking without retaining unbounded',
+    '  // payload closures when Orca is down and each POST waits for timeout.',
+    '  if (postQueue.length >= MAX_PENDING_POSTS) {',
+    '    postQueue.shift()',
+    '  }',
+    '  postQueue.push({ hookEventName, payload })',
+    '  void drainPostQueue()',
     '}',
     '',
     'export default function (amp: PluginAPI) {',