docs: record Phase 5 commit hash in PLAN.md

PLAN.md

@@ -24,7 +24,7 @@ Goal: full-parity native iOS app per UPDATE_PATH.md, verified in simulator via X
 - [x] Phase 2: LiveKit session spike — commit 4986b6d (mic -4010 is sim env limitation; verify on device)
 - [x] Phase 3: state machine, audio levels, wake lock, history (commit 5483e6e)
 - [x] Phase 4: voice/model pickers with sync-on-join (commit ca2d26f)
-- [x] Phase 5: media player — commit 17e1e27 (webm playback blocked by iOS AVPlayer; see status below)
+- [x] Phase 5: media player — commit 0af944e (webm playback blocked by iOS AVPlayer; see status below)
 - [ ] Phase 6: media search, choices, library panel
 - [ ] Phase 7: background tasks panel (task_event fold-in)
 - [ ] Phase 8: polish/hardening/parity pass