Post-merge cleanup of PR #805:
1. Extract duplicate error classification logic into classifyDatabaseError()
helper function (was duplicated in two places in database.go)
2. Fix semantic conflict between --force and --source=db flags:
- --force implies "database is broken, rebuild from JSONL"
- --source=db implies "use database as source of truth"
- These are contradictory; now errors with clear message
- --force with --source=auto or --source=jsonl works as expected
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Executed-By: beads/crew/dave
Rig: beads
Role: crew
eefeb1a5bc