fix(overview): timeout hung ScreenCaptureKit calls

[qeude]

Summary

• Wrap ScreenCaptureKit calls with 5-second timeout to prevent indefinite hangs that block the capture limiter
• Release limiter slot immediately on timeout so subsequent overview sessions can proceed instead of waiting for restart
• Apply timeout to: SCShareableContent fetch, desktop background captures, and window preview captures
• Add withOverviewCaptureTimeout() helper using Task.sleep-based deadline with first-completion semantics
• Add unit test verifying timeout behavior and limiter recovery
• Add agent skill documentation for Defi feature verification (overview, navigation, workspaces, service lifecycle)

Testing

• New test hungNativeCaptureFailsAtDeadlineInsteadOfHoldingTheSlot verifies timeout fires and limiter releases
• Local: python3 script/verify.py local (swift build and non-desktop tests)
• Desktop E2E: existing testOverviewShowsBothMonitorsBeforeLoadingPreviews exercises the capture flow
• Manual: defi toggle-overview && sleep 3 && defi status should show overviewReceivedPreviews > 0

Note

Timeout hung ScreenCaptureKit calls in overview capture paths

• Adds withOverviewCaptureTimeout in OverviewPreviewCapture.swift, a main-actor wrapper that races a capture operation against a 5-second deadline and throws OverviewCaptureTimeoutError. The hung native call is not cancelled; the wrapper just stops waiting on it.
• Wraps shareable-content discovery, desktop screenshots, and window screenshots in captureOverviewImages, and shareable-content discovery plus sample-buffer capture in OverviewSurfaceCapture.prepare. Timeout errors follow the existing error paths and release the capture limiter slot.
• Bounds desktop background capture retries to 5 per overview session generation in OverviewController.swift; after exhaustion, window previews still schedule, and a new generation resets the count.
• Adds tests in OverviewPreviewTests.swift covering the deadline failure and limiter release to queued captures.
• Behavioral Change: overview captures now fail after 5 seconds instead of blocking indefinitely; the underlying ScreenCaptureKit call keeps running after the timeout, and desktop backgrounds are skipped after 5 failed retries in a session.

^{Macroscope summarized 44c31e1.}

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no new actionable issues were found.

Summary

Overview captures now stop waiting after five seconds and release the shared capture slot.

• Overview captures stop waiting after five seconds.
• Desktop background retries stop after five attempts per session.
• Agents can follow a shared guide to verify Defi features.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Acquire capture slot] --> B[Start native capture and deadline]
  B --> C{Which finishes first?}
  C -->|Capture| D[Return image or error]
  C -->|Five seconds| E[Return timeout error]
  D --> F[Release capture slot]
  E --> F
  E --> G[Native call remains running]

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_{Reviews (6) · Last reviewed commit: "Merge branch 'main' into t3/overview-cap..." · Reviewed by Greptile}

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This targeted overview reliability fix changes production capture scheduling by abandoning timed-out ScreenCaptureKit calls and automatically suppressing desktop retries after five failures per session. The concurrency and limiter interactions, along with the new retry gate, warrant human review.

No code changes detected at 44c31e1. Prior analysis still applies.

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