fix(chrome-extension): keep camera preview alive across tab hand-offs and retry failed connects

[ManthanNimodiya]

Fixes the "front camera never loads again after switching tabs" report from Discord.

Two problems combined: switching tabs stopped and reopened the physical camera with no synchronization, and the preview iframe had no retry, one failure left the tile dead until camera settings changed, which is why deselect/reselect fixed it.

• Offscreen doc keeps the shared camera stream warm for 2s across hand-offs, registers new sessions before the stream await, and dedups concurrent getUserMedia calls
• Preview iframe retries failed connects with capped backoff (skipping permission errors) and reconnects when the remote track ends, stays muted, or the peer fails

Repro: with the preview live, seize the camera with another app and switch tabs, previously the tile stayed dead after freeing the camera; now it recovers on its own.

Greptile Summary

This PR keeps camera previews alive during tab hand-offs and reconnects failed previews. The main changes are:

• Deduplicate concurrent camera acquisitions by device.
• Delay camera release for two seconds after the last session disconnects.
• Register replacement sessions before awaiting camera access.
• Retry recoverable connection failures with capped backoff.
• Reconnect when remote tracks end, remain muted, or peers fail.

Confidence Score: 4/5

Transient peer disconnections can unnecessarily restart an otherwise recoverable preview.

• Shared camera ownership and stale-session handling cover the main hand-off races.
• Retry timers are cleared when the effect is disposed.
• The disconnected state currently triggers immediate teardown instead of allowing recovery.

apps/chrome-extension/src/preview/camera-preview.tsx

Important Files Changed

Filename	Overview
apps/chrome-extension/src/offscreen/recorder.ts	Adds delayed stream release, acquisition deduplication, and session registration before camera acquisition.
apps/chrome-extension/src/preview/camera-preview.tsx	Adds retry and liveness handling, but treats a transient peer disconnection as terminal.

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
apps/chrome-extension/src/preview/camera-preview.tsx:505-509
**Transient Disconnect Tears Down Preview**

A peer can enter `disconnected` briefly and recover to `connected`, but this branch immediately closes it and starts another camera hand-off. A temporary connection interruption therefore causes an avoidable black frame and camera restart instead of allowing the active peer to recover.

```suggestion
				if (
					peer.connectionState === "failed" ||
					peer.connectionState === "closed"
				) {
```

_{Reviews (1): Last reviewed commit: "fix(chrome-extension): keep camera previ..." | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

Context used:

• Context used - CLAUDE.md (source)
• Context used - AGENTS.md (source)

[greptile-apps]

Transient Disconnect Tears Down Preview

A peer can enter disconnected briefly and recover to connected, but this branch immediately closes it and starts another camera hand-off. A temporary connection interruption therefore causes an avoidable black frame and camera restart instead of allowing the active peer to recover.

Suggested change

	if (
	peer.connectionState === "failed" ||
	peer.connectionState === "disconnected" ||
	peer.connectionState === "closed"
	) {
	if (
	peer.connectionState === "failed" ||
	peer.connectionState === "closed"
	) {

Prompt To Fix With AI

This is a comment left during a code review.
Path: apps/chrome-extension/src/preview/camera-preview.tsx
Line: 505-509

Comment:
**Transient Disconnect Tears Down Preview**

A peer can enter `disconnected` briefly and recover to `connected`, but this branch immediately closes it and starts another camera hand-off. A temporary connection interruption therefore causes an avoidable black frame and camera restart instead of allowing the active peer to recover.

```suggestion
				if (
					peer.connectionState === "failed" ||
					peer.connectionState === "closed"
				) {
```

How can I resolve this? If you propose a fix, please make it concise.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

[tembo]

Minor: when reconnect() runs, it might leave retryTimer / muteTimer pending (they’ll no-op due to peerRef guard, but still keep closures alive). Clearing them here avoids stray timers and makes the reconnect path a bit tighter.

Suggested change

	const reconnect = () => {
	if (disposed || peerRef.current !== peer) return;
	stopPreview();
	void startPreview(0);
	};
	const reconnect = () => {
	if (disposed || peerRef.current !== peer) return;
	clearRetryTimer();
	clearMuteTimer();
	stopPreview();
	void startPreview(0);
	};