performance updates for obs-zoom-to-mouse.lua?

[bingbangboom-lab]

Changes:

• Added threshold check before updating crop filter (only calls OBS API if change > 0.5px)
• Throttled mouse position polling to 30ms instead of every frame
• Deferred scene item refresh by 150-200ms to avoid race conditions on startup
• Added retry logic for source size detection (fixes random init failures)
• Added compatibility wrappers for obs_sceneitem_get_info (handles API changes in newer OBS versions)

Tested on: Windows 11, OBS Studio 32.0.2. The macOS and Linux changes are based on the existing FFI code patterns in the script -- didn't change the actual platform logic, just added error handling and fallbacks.