v0.57.12: Spec approval with comment and input stability

New features

- Spec approval with comment - Added a "Proceed with comment" option to spec approval, letting you approve a spec and attach a guiding comment in one action

Bug fixes

- Fast model switching - Fixed edge cases when switching models mid-conversation, including proper conversation state management
- Invalid MCP output schemas - Tolerates invalid MCP tool output schemas instead of crashing
- Opus 4.5 max tokens - Corrected incorrect Opus 4.5 max output tokens in model registry
- Ctrl+O during AskUser - Allows Ctrl+O (open in editor) during the AskUser tool flow
- AskUser context - Ensures context is clear when using the AskUser tool
- Session file table overflow - Limits concurrency when fetching sessions in daemon to avoid "file table overflow" errors
- Duplicate plan steps - Fixed duplicate plan steps in web UI when multiple TodoWrite calls share the same title (Factory App)