fix: correct image source path and enhance error handling for image loading

[EndoTheDev]

PR summary

• Fix resource path casing and harden GuLuLu image handling in web/gululu.js to prevent runtime errors when the image is missing or not yet loaded.

What changed

• Corrected image source path casing:
  • "/extensions/kaytool/resources/GuLuLu.gif" -> "/extensions/KayTool/resources/GuLuLu.gif"
• Added image load error handler:
  • Logs a warning and clears pixelDataCache on img.onerror.
• Added readiness checks before drawing:
  • Skip drawing and clear cache if image is not present, not complete, or has zero natural width.
• Wrapped drawImage/getImageData in try/catch:
  • Logs a warning and clears pixelDataCache on failure to avoid uncaught exceptions.
• Minor: ensured newline at end of file.

Motivation

• Prevents uncaught exceptions from drawImage/getImageData when the image fails to load or is not ready.
• Fixes a casing bug that can break resource lookup on case-sensitive filesystems/servers.
• Improves stability and logging so failures are observable without breaking the UI.

Testing / QA steps

1. Load the app and confirm GuLuLu renders and animates when the GIF is present.
2. Rename or remove web/resources/GuLuLu.gif to simulate a missing resource; confirm:
   • No uncaught exceptions in console.
   • A console warning "KayTool: GuLuLu image failed to load" appears.
   • No visual crashes; pixelDataCache is cleared.
3. Resize the window/container and verify no errors occur and behavior remains correct when the image is available.
4. Verify the extension folder name is KayTool (capitalization) on the deployment environment.