Add Token statistics API

Fix startup on AGX Orin with JetPack 7.2.1 while retaining JetPack 6.2.1 compatibility. Update Tiny, Small, and Medium compatible engine caches with verified Hugging Face and ModelScope downloads. Fix recovery after invalid images or inference errors so subsequent requests continue to run. Validate all three model sizes across both systems; recognized text, boxes, and confidence scores remain identical.

Align the installer prompt and button with the AI Pod model layout, with Chinese and English text linking to the PP-OCRv6 deployment page.