This PR resolves two critical issues in Continuity: unintended MTS pack resource loading and NPE crashes from invalid input streams—with targeted changes across 3 core classes (backward-compatible for non-MTS packs).

Key Changes

1. ResourceRedirectHandler.java

   • Add MTS validation via pack.mcmeta (whitelists valid paths via mts.validResources`).
   • Restrict redirection to mts/continuity namespaces; validate post-redirect paths.

2. CtmPropertiesLoader.java

   • Whitelist MTS CTMs via pack.mcmeta(loads valid paths from mts.validCtmPaths).
   • Check for null input streams to fix NPEs; validate CTM-dependent textures.
   • Enhance logs with pack/path details for troubleshooting.

3. AtlasLoaderMixin.java

   • Add null checks for emissive texture input streams (fixes crash source).
   • Validate MTS legitimacy for base/emissive textures; secure thread context handling.

MTS Pack Requirement
Add mts field to pack.mcmeta (example) for validation:
{
"mts": {
"validResources": ["mts:textures/block/stone.png"],
"validCtmPaths": ["optifine/ctm/mts_stone.ctm.properties"]
}
}

Fixed Issues

• ✅ Stops loading unlisted MTS resources/CTMs.
• ✅ Eliminates NPE crashes from invalid streams.
• ✅ Improves MTS compatibility without breaking non-MTS packs.