Update README.md

Updated demo link in README to new asset location.

Add demo video to README

Refactor to state-machine-first architecture with YouTube fix

Add model selection and stop button

Fix navigation from restricted pages (new tab, chrome://)

Disable Vision Mode - MV3 CSP blocks remote scripts

Fix CSP to allow ONNX runtime from jsdelivr CDN

Fix popup connection handling and add reconnection logic

Complete VisionExecutor integration for testable vision mode

Add VLM support with Transformers.js for screenshot-based navigation

Initial commit: On-Device Browser Agent POC