v0.125.0: ACP config options, larger Task results, and stability fixes

New features

- ACP config options - The CLI now advertises configuration options to ACP clients and supports session/set_config_option for per-session overrides

Improvements

- Larger Task tool results - Raised the truncation limit on Task tool results so more output is preserved

Bug fixes

- Stale tool shimmer - Tool calls no longer leave a stale shimmer behind in the transcript
- Stale Slack shimmer heartbeat - Stopped a stale shimmer heartbeat from lingering in Slack threads
- Return to session on interaction prompt - The CLI now returns to the session view when a user interaction box surfaces
- Gemini thinking signatures on replay - Gemini thinking signatures are now preserved when sessions replay
- Title bar path on hover - The title bar now shows the full working directory path on hover (app)