…npacking them

The client loads fonts and updater .xnb files directly from the file system and doesn't have support for unpacking them from asset packs. Only sounds and music have AssetPacker support on the client side.

Changes:
- Removed fonts directory from texture scanning (contains only .xnb files, not PNGs)
- Kept updater directory in texture scanning (can contain PNG files like progressbar.png)
- Removed fonts.index packing code (not supported by client)
- Removed updater.index packing code (not supported by client)
- Added comments explaining why these directories are handled differently
- Textures (PNG files) are still packed from all appropriate folders including updater

This ensures only assets that the client can unpack are included in asset packs.

Fixed two critical issues with asset packing and uploading:

1. Asset Packing Path Format:
   - Changed texture paths to use relative format matching GameContentManager
   - Textures now use paths like "resources/items/sword.png" (relative to root)
   - This ensures .meta files contain correct paths for upload exclusion logic
   - Paths are normalized with forward slashes for cross-platform compatibility

2. Upload Exclusion Logic Fix:
   - Fixed texture exclusion to work with full relative paths in .meta files
   - Removed redundant Path.Combine that was creating incorrect double "resources/" prefix
   - Now correctly matches packed texture filenames like "resources/items/sword.png"
   - Exclusion logic now properly excludes source files when uploading packed assets

These changes ensure that when asset packing is enabled, only the packed .asset and .meta
files are uploaded, and the original source PNG/WAV/OGG files are correctly excluded.