v0.2.3

Added

• Persistent no-date cache (no_date_cache.json, stored next to config.toml): files
  that fail capture-date extraction are remembered across scan cycles and silently skipped
  until their modification time changes or the TTL expires. Previously, the same files
  generated a WARN log on every 30-second scan cycle.
• New global config options:
  • no_date_cache_enabled (default true): set to false to disable the cache and
    always re-scan every file.
  • no_date_cache_ttl_days (default 0 = never expire): set e.g. 30 to retry files
    without metadata once a month regardless of mtime.
• Cache is invalidated automatically when a file's mtime changes (e.g. EXIF added via
  exiftool), so modified files are always re-processed without manual intervention.
• postuninst() hook in SPK installer: deletes no_date_cache.json on package
  uninstall while preserving the user's config.toml.

Changed

• processor::process_file() now returns Err(ProcessorError::CaptureDataNotFound)
  instead of Ok(()) when no capture date is found. The watcher emits the WARN log
  once (on first discovery) and then silently skips the file via the cache.

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