- log.go: log level system (DEBUG, INFO, WARN, ERROR, NONE)
- CLI: -log-level flag (default info), -verbose as shorthand for debug
- Watcher: logs sync/remove actions at INFO level
- Watcher: logs events at DEBUG level
- Errors: structured error messages (DISK FULL, PERMISSION DENIED, etc.)
- Updated README with -log-level flag

- syncCreate: remove existing file before creating symlink
- syncWrite: handle symlink target changes (remove + recreate)
- Added 4 new tests:
  - CreateSymlink: new symlink synced to /data
  - UpdateSymlinkTarget: symlink target change updates /data
  - RemoveSymlink: symlink removal synced
  - ModifySymlinkTargetFile: target file change preserves symlink
- 39 tests passing

- Replaced go-gitignore with custom GitignoreStack that tracks
  multiple .gitignore files hierarchically
- Patterns are processed in root-to-leaf order, last match wins
- Negation patterns in child dirs override parent ignores
- Patterns only apply within their directory scope (no leaking)
- Added 6 new tests for nested .gitignore:
  - Scoped: patterns only affect own directory
  - Dir-scoped: different dirs can ignore different things
  - Negation override: child !pattern un-ignores parent's *.pattern
  - Deep nesting: 3+ levels of .gitignore
  - Parent scope doesn't leak to siblings
- All 35 tests passing

- Added watcher_test.go: 10 tests covering create, write, remove,
  rename, ignored files, debouncing, directory creation/removal,
  and manifest updates
- Refactored watch() to accept context.Context for clean cancellation
- Added signal handling (SIGINT/SIGTERM) for graceful shutdown in main.go
- Fixed test expectations (version two = 11 bytes, not 10)