feat(tags): add multi-file and subdirectory support for tags

[AndresCS20]

Summary

• Add recursive subdirectory support for loading tag YAML files from any nested folder
• Fix NullPointerException when rarity is not specified in tag config (now defaults to "common")
• Refactor tag loading to support multiple YAML files with proper source tracking
• Tags are now saved/deleted to the correct source file

Changes

• Modified ConfigManager.reloadTagConfigs() to recursively find all .yml files
• Added getAllYamlFiles() helper method for directory traversal
• Changed TagManager.loadTags() to iterate over all tag config files
• Added tagSourceConfig map to track which file each tag was loaded from
• Updated all save/delete methods to use the correct source file
• Fixed rarity loading: section.getString("rarity", "common") instead of section.getString("rarity")

Testing

• Verified all tags load correctly from nested folders
• Verified validation/saving works on correct file location
• Tested rarity handling with and without explicit rarity field

Breaking Changes

None - fully backward compatible

Example Structure

tags/ ├── default.yml ├── countries/ │ ├── spain.yml │ └── argentina.yml └── flags/ ├── ocean.yml └── mountain.yml

Related Issue

Fixes NullPointerException: "Cannot invoke String.equalsIgnoreCase because getRarity() is null"