- Add input validation for texture dimensions (max 8192x8192)
- Add integer overflow protection before memory allocation
- Add null pointer validation before buffer operations
- Fix exception handling to use references instead of values
- Add OpenGL error checking before/after critical operations
- Add comprehensive bounds checking in changeSize() method
- Add memory allocation error handling with try-catch blocks

Fixes crash with Exception Code 0xC0000409 (FAST_FAIL_FATAL_APP_EXIT)
that was occurring in FlutterDesktopTextureRegistrarMarkExternalTextureFrameAvailable

…o avoid partial reads and flicker

- Update structure.width/height in buffer mode
- Recreate framebuffer/renderbuffer when buffer size changes
- Avoid duplicate FBO creation at init (setup handled after changeSize)

Improves stability of PixelBufferTexture reads and texture updates