Land release blocker fixes and workspace cleanup

docs/issues/c1-live-session-race.md

@@ -4,6 +4,31 @@
 **Path:** `src-tauri/src/commands/live.rs:193-338`
 **Source:** [2026-04-22 code review](../code-review-2026-04-22.md#c1--racy-single-session-guard-in-livers)
 **Labels:** release-blocker, critical, concurrency
+**Status:** RESOLVED (2026-04-22)
+
+## Resolution
+
+`LiveTranscriptionState` now includes a dedicated
+`tokio::sync::Mutex<()>` lifecycle gate. Both
+`start_live_transcription_session` and
+`stop_live_transcription_session` acquire that async mutex before
+touching `running`, and they keep it held across the awaited setup /
+join work that previously exposed the race windows.
+
+That changes the two failing interleavings from the review:
+
+- Two overlapping starts no longer race through the empty-slot check.
+  The second call waits for the first to finish setup, then observes
+  `running.is_some()` and returns the existing
+  `"A live transcription session is already running"` error.
+- A start launched during stop can no longer sneak in after
+  `running.take()` but before the previous worker has fully joined.
+  It blocks on the lifecycle mutex until the join completes.
+
+Regression tests in `commands::live::tests`:
+
+- `concurrent_starts_allow_only_one_session_to_claim_the_slot`
+- `start_waits_for_stop_to_finish_joining_before_reusing_slot`
 
 ## Problem
 
@@ -26,4 +51,4 @@ Large. Will likely require the `run_live_session` monolith refactor (RB-04) to l
 
 ## Dependencies
 
-- **Blocked by:** RB-04 (`run_live_session` monolith refactor)
+- Landed after RB-04 (`run_live_session` refactor) made the worker lifecycle explicit enough to guard safely.