Split send state into explicit worktree and turn phases

- Replace boolean `isSending` with `sendPhase` state
- Show "Preparing worktree..." status before first-turn dispatch
- Keep composer editable while preventing duplicate sends and restore input on pre-send failures
8edbf4b7a0Julius Marminge committed on 2/27/2026, 3:48:58 AMparent68585d4
1 file changedLine totals unavailable