- Notifier + FocusTimer fields in Daemon, initialized in NewDaemon
- processHookEvent notifies on Working -> Needs Input only (D-01)
- Focus mode suppresses notifications when active (D-05)
- FocusArgs in protocol, "focus" handler in daemon
- CLI "vmux focus <minutes>" command
- Tests for all notification transitions and focus handler
- TailReadJSONL: reverse-read JSONL without loading entire file
- FindSessionForProcess: match PID to most recent JSONL via EncodePath
- DetectState: heuristic based on last message stop_reason + tool name
- ExtractPreview: extract first 3 lines of last assistant text
- All 17 tests pass (session_test.go + state_test.go)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>