docs: mark Phase 4 done with commit hash

PLAN.md

@@ -23,7 +23,7 @@ Goal: full-parity native iOS app per UPDATE_PATH.md, verified in simulator via X
 - [x] Phase 1: ServerConfig/TokenClient/TLSPinning/ConnectionTest (commit 378b8cb)
 - [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 pending)
+- [x] Phase 4: voice/model pickers with sync-on-join (commit ca2d26f)
 - [ ] Phase 5: media playback reconciliation + AVPlayer + local reverse proxy for self-signed https media
 - [ ] Phase 6: settings parity (text mode done in Phase 3; remaining polish)
 - [ ] Phase 7: polish/edge cases