feat: add timeout param to record_video for auto-stop

[saen-ai]

Summary

Adds an optional timeout parameter (integer, 1–3600 seconds) to record_video. When provided, the recording automatically stops after the specified duration without needing a separate stop_recording call.

Fixes #5

How it works

After the recording starts successfully, a setTimeout fires at the given duration and sends SIGINT to the tracked ChildProcess (the same targeted kill introduced in #64). The activeRecordings map is cleaned up automatically on process exit.

Changes

• Added timeout: z.number().int().positive().max(3600).optional() to record_video schema
• Auto-stop logic fires SIGINT via the tracked PID after timeout * 1000 ms
• Success message adapts: shows countdown note when timeout is set, otherwise shows manual stop instruction

Test plan

• Call record_video without timeout → records indefinitely, stopped by stop_recording
• Call record_video with timeout: 5 → recording stops automatically after ~5 seconds, video file is saved
• Call record_video with timeout: 5, then call stop_recording before 5s → stops immediately, timer fires harmlessly after (process already gone)
• Call record_video with timeout: 3601 → Zod validation error (exceeds max)

[joshuayoes]

Thanks — clean feature, fixes #5. Fits the spawned-process pattern from #64 well. Three things:

1. Stacking. Same as feat: add max_size and force params to screenshot tool #63/fix: track recording process by UDID for targeted stop #64. Net-real-change is commit 87af28aa, but it depends on 611e44e5 from fix: track recording process by UDID for targeted stop #64. Cleanest path: once fix: track recording process by UDID for targeted stop #64 lands on main, rebase this PR onto upstream/main with just 87af28aa. If you want to unblock before that, a branch containing 611e44e5 + 87af28aa (in that order) works too.

   # after #64 is merged
   git fetch upstream
   git checkout -B feat/record-video-timeout upstream/main
   git cherry-pick 87af28aa
   git push --force-with-lease origin feat/record-video-timeout
   

2. Unreffed setTimeout. The timer keeps the Node event loop alive until it fires, even if the recording was manually stopped before that via stop_recording. The activeRecordings.get(...) lookup returns undefined after the exit handler runs, so no stray kill — good — but the event-loop keepalive is still there. Either .unref() the timer, or clearTimeout in the exit handler. Small polish, not blocking.

3. Demo recording. ## Demo with a short recording showing e.g. record_video with timeout: 5 auto-stopping would be great — see Releases and feat: add ui_find_element tool #51 for format.