Enhanced Metadata Handling (RandomString)

[nu1lkali]

This PR introduces several significant improvements to the Flut Renamer application, enhancing both functionality and robustness.

Key Changes

1. New Logging System (lib/tools/logger.dart)

   • Singleton logger with real-time log streaming
   • Timestamped log entries with stream support

2. Enhanced Metadata Handling (lib/tools/file_metadata.dart)

   • Added OS:UUID and OS:RandomString metadata fields
   • Improved error handling and tag detection regex

3. Updated Replace Rule (lib/rules/rule_replace.dart)

   • Added {RandomString} tag support (8-digit random string)
   • Enhanced tag detection and parsing

4. Dependency Update (pubspec.yaml)

   • Added uuid: ^4.4.0 package for UUID generation

[nu1lkali]

New: Support sharing files from the system photo gallery to Flut-Renamer
(i18n internationalization not yet supported)