Flatten paths and trim filenames

[Nogard-YT]

Some platforms have an 80 character path length limit, and longer paths prevent the pack from loading. To fix this:

Flattened paths: files go directly into folders, no more nested subdirectories. Example: entity/pets/baby_breeze_pet.entity.json becomes entity/baby_breeze_pet.json. Minecraft Java of ModelEngine also does it this way.

Shorter filenames: dropped verbose suffixes like .animation.json, .geo.json, .entity.json, .animation_controllers.json. Everything is just .json now.

Namespaced render controllers: added meg_ prefix to avoid vanilla conflicts. For example, controller.render.happy_ghast becomes controller.render.meg_happy_ghast, and the file is now meg_happy_ghast.json instead of controller.render.happy_ghast.json

Better geometry names: model-specific instead of generic. Geometry.default becomes Geometry.modelId, Geometry.t_64_64 becomes Geometry.modelId_64_64

Fixed animated texture fps: values above 60 now cap to 7.0 (standard Bedrock speed). Fixes broken configs that had fps set to 1000.

[zimzaza4]

Thank you for your PR! but pack generator has been merged into GeyserModelEngine: https://github.com/GeyserExtensionists/GeyserModelEngine/tree/main/geyser