fix(desktop): rearm voice conversation after stop (#108301)

[Tranquil-Flow]

What

Fixes #108301.

Desktop voice conversation mode now treats Stop/Esc during read-aloud as a reply-only interruption, not as the end of hands-free mode:

• consumes the interrupted pending response when an external Stop is observed, so it cannot be replayed later;
• re-arms the microphone whenever the conversation is still enabled;
• preserves the barge-in capture early return so an active barge monitor still owns the mic instead of starting a second capture.

Why

The previous settleAfterSpeech() path detected an external stop via the voice playback sequence and then skipped pendingStartRef.current = true. The UI remained in voice-conversation mode, but the mic never reopened. It also left the stopped pending response available to future playback consumers.

Verification

Run from apps/desktop after rebasing onto current upstream/main:

• npx vitest run --project ui src/app/chat/composer/hooks/use-voice-conversation-rearm.test.tsx src/app/chat/composer/hooks/use-voice-conversation.test.tsx --reporter=default → 2 files passed, 11 tests passed. Existing React act(...) warning in the barge-in suite is unchanged.
• npx eslint src/app/chat/composer/hooks/use-voice-conversation.ts src/app/chat/composer/hooks/use-voice-conversation-rearm.test.tsx → passed.
• npm run typecheck → passed.
• git diff --check → passed.

RED proof captured in .automation/runs/20260911T1604Z/108301/fail-without-fix.txt: 3 regression tests failed on the pre-fix production code, each with the mic start count stuck at 1 instead of re-arming to 2.

Duplicate / competitor check

• Same-issue open PR search for 108301 in:title,body state:open: none.
• Same-author open PR check for Tranquil-Flow:fix/108301*: none before publication.
• Topic-overlap PR fix: keep listening after stopping a voice-conversation reply #81176 was reviewed. It covers the basic re-arm symptom, but does not consume the interrupted pending response or cover the stale-replay layer from [Bug]: Desktop voice conversation becomes deaf after stopping read-aloud (stop re-arms nothing) #108301; scored 6.5/10 under the pipeline duplicate policy, so it is not blocking.

Auto-published by Moonsong via Path B automated pipeline.

[alt-glitch]

This was generated by AI during triage.

Related: #81176 (open since 2026-08-07) removes the same stoppedByUser gate in settleAfterSpeech so the mic re-arms after an external Stop; this PR additionally consumes the interrupted pending response and preserves the barge-in early return. Competing fixes for #108301 - a maintainer should pick one (or fold the pending-response consumption into #81176).

[kvnloo]

Comment assumes head 898757948b5f92e5d5faeff05af20e782dabaa84; void if moved.

CHECK — Desktop voice-conversation re-arm after Stop (#108301)

• Treating Stop/Esc during read-aloud as reply-only interruption (consume interrupted pending + re-arm mic while conversation still enabled + preserve barge-in early return) is a valuable re-arm fix for stuck hands-free mode.
• This is not a new Desktop lifetimes vehicle — Rank3 fix(desktop): isolate voice turn lifetimes #95180 (@ bee79171eacf6eb810a208ec8d3154a8891bb2e0) already owns capture/turn lifetime isolation. Prefer fix(desktop): isolate voice turn lifetimes #95180’s contracts; adapt this re-arm so it cannot submit/stop/re-arm a superseded turn.

CHECK (desk / competitors)

• GitHub reports MERGEABLE but mergeStateStatus: BLOCKED with empty live status rollup — rebase onto current main (prefer post-fix(desktop): isolate voice turn lifetimes #95180 tip when available) and re-run focused Vitest (use-voice-conversation-rearm / use-voice-conversation) + typecheck before merge desk.
• Competitor fix: keep listening after stopping a voice-conversation reply #81176 still OPEN for the same settleAfterSpeech / stoppedByUser re-arm symptom; this PR adds pending-response consumption + barge-in early-return preservation. Maintainer should pick one re-arm vehicle (or fold the pending-response consume into fix: keep listening after stopping a voice-conversation reply #81176) — do not land both gates.
• Shared hook with Fresh Desktop/live (feat(voice): add Codex OAuth STT, TTS, and live voice #106640 / feat(desktop): add ElevenLabs realtime voice transcription #94113) and Rank3 (fix(desktop): isolate voice turn lifetimes #95180): use-voice-conversation* — conflict/ordering expected; folding lifetimes or provider surfaces into this PR is wrong-face.
• Wrong-face vs Rank1: re-arm is not a duplex ABC (feat(voice): add realtime provider session contract #95147/[RFC] RealtimeVoiceProvider ABC — four competing duplex-voice PRs need an interface, not a merge queue #77111).
• Do not fold cascaded TTS (feat(tts): add Groq Orpheus as a first-class TTS provider #98105), Rank2 web, occluded-metering (fix(desktop): finish voice turns while the window is minimized or occluded #110981), or Muse metas into this PR.

One-click close / ordering

• Close competing Stop-during-read-aloud leaves conversation armed but mic dead / [Bug]: Desktop voice conversation becomes deaf after stopping read-aloud (stop re-arms nothing) #108301 duplicates only after the chosen re-arm vehicle lands and they are true duplicates.
• Do not close or absorb fix(desktop): isolate voice turn lifetimes #95180, fix: keep listening after stopping a voice-conversation reply #81176 (until decision), feat(voice): add Codex OAuth STT, TTS, and live voice #106640, feat(desktop): add ElevenLabs realtime voice transcription #94113, feat(voice): add realtime provider session contract #95147, Discord voice mode has extreme latency or poor STT accuracy #94462, or feat(tts): add Groq Orpheus as a first-class TTS provider #98105 into this PR.
• If fix(desktop): isolate voice turn lifetimes #95180 lands first, rebase here afterward and cite that merge SHA.

Landing-evidence

• When merged, please reply with the merge commit SHA on main (not “completed”).

[kvnloo]

Comment assumes head 898757948b5f92e5d5faeff05af20e782dabaa84; void if moved.

CHECK — Desktop voice-conversation re-arm after Stop (#108301)

• Treating Stop/Esc during read-aloud as reply-only interruption (consume interrupted pending + re-arm mic while conversation still enabled + preserve barge-in early return) is a valuable re-arm fix for stuck hands-free mode.
• This is not a new Desktop lifetimes vehicle — Rank3 fix(desktop): isolate voice turn lifetimes #95180 (@ bee79171eacf6eb810a208ec8d3154a8891bb2e0) already owns capture/turn lifetime isolation. Prefer fix(desktop): isolate voice turn lifetimes #95180’s contracts; adapt this re-arm so it cannot submit/stop/re-arm a superseded turn.

CHECK (desk / competitors)

• GitHub reports MERGEABLE but mergeStateStatus: BLOCKED with empty live status rollup — rebase onto current main (prefer post-fix(desktop): isolate voice turn lifetimes #95180 tip when available) and re-run focused Vitest (use-voice-conversation-rearm / use-voice-conversation) + typecheck before merge desk.
• Competitor fix: keep listening after stopping a voice-conversation reply #81176 still OPEN for the same settleAfterSpeech / stoppedByUser re-arm symptom; this PR adds pending-response consumption + barge-in early-return preservation. Maintainer should pick one re-arm vehicle (or fold the pending-response consume into fix: keep listening after stopping a voice-conversation reply #81176) — do not land both gates.
• Shared hook with Fresh Desktop/live (feat(voice): add Codex OAuth STT, TTS, and live voice #106640 / feat(desktop): add ElevenLabs realtime voice transcription #94113) and Rank3 (fix(desktop): isolate voice turn lifetimes #95180): use-voice-conversation* — conflict/ordering expected; folding lifetimes or provider surfaces into this PR is wrong-face.
• Wrong-face vs Rank1: re-arm is not a duplex ABC (feat(voice): add realtime provider session contract #95147/[RFC] RealtimeVoiceProvider ABC — four competing duplex-voice PRs need an interface, not a merge queue #77111).
• Do not fold cascaded TTS (feat(tts): add Groq Orpheus as a first-class TTS provider #98105), Rank2 web, occluded-metering (fix(desktop): finish voice turns while the window is minimized or occluded #110981), or Muse metas into this PR.

One-click close / ordering

• Close competing Stop-during-read-aloud leaves conversation armed but mic dead / [Bug]: Desktop voice conversation becomes deaf after stopping read-aloud (stop re-arms nothing) #108301 duplicates only after the chosen re-arm vehicle lands and they are true duplicates.
• Do not close or absorb fix(desktop): isolate voice turn lifetimes #95180, fix: keep listening after stopping a voice-conversation reply #81176 (until decision), feat(voice): add Codex OAuth STT, TTS, and live voice #106640, feat(desktop): add ElevenLabs realtime voice transcription #94113, feat(voice): add realtime provider session contract #95147, Discord voice mode has extreme latency or poor STT accuracy #94462, or feat(tts): add Groq Orpheus as a first-class TTS provider #98105 into this PR.
• If fix(desktop): isolate voice turn lifetimes #95180 lands first, rebase here afterward and cite that merge SHA.

Landing-evidence

• When merged, please reply with the merge commit SHA on main (not “completed”).