When database is stale and a read-only command runs in --no-daemon mode,
auto-import from JSONL instead of returning an error. This fixes `gt sling`
failing with 'not a valid bead' after git pull.
Root cause: `ensureDatabaseFresh` would return an error when DB was stale,
but read-only commands like `bd show` should be able to auto-import and
proceed rather than blocking the user.
Changes:
- Modify ensureDatabaseFresh to call autoImportIfNewer() when stale
- Only error if --no-auto-import flag is explicitly set
- Add comprehensive tests for all staleness scenarios
Fixes: bd-9dao
Co-authored-by: Claude <noreply@anthropic.com>
