feat(session): add session lifecycle management with auto-reset triggers
- Add session management functions: get_session_id(), reset_session(),
log_session_transition(), init_session_tracking()
- Session auto-reset on: circuit breaker open, manual interrupt,
project completion, manual circuit reset
- Add --reset-session CLI flag for manual session reset
- Add session history tracking (.ralph_session_history, last 50 entries)
- New config: RALPH_SESSION_FILE, RALPH_SESSION_HISTORY_FILE
- Add 26 comprehensive tests for session continuity (TDD)
- All 265 tests pass (up from 239)
- Update CLAUDE.md with v0.9.7 release notes
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