Dual-Engine Runtime with E2EE IPC and Global Bindings

[yumin-chen]

This submission implements a secure dual-engine architecture for AlloyScript.

Key changes:

1. Dynamic Bindings: Added JS_BindGlobal to MicroQuickJS and webview_bind_global to the WebView core, enabling runtime C-to-JS function mapping.
2. E2EE IPC: Redesigned the communication bridge between the trusted C host and the untrusted WebView. Communication is now fully encrypted via AES-256-GCM with keys exchanged via X25519.
3. Defense in Depth: The WebView is now hidden by default and acts only as a provider for browser-native APIs. All core application logic executes within an isolated MicroQuickJS environment in the host process.
4. Codebase Reorganization: Separated third-party dependencies (MicroQuickJS, WebView) into deps/ under MIT licenses and moved primary engine logic to src/ under CC0.
5. Security Hardening: Implemented secure JSON parsing in C via SQLite and fixed memory safety issues in the crypto implementation.
6. Documentation: Updated ReadMe.md to detail the new architecture and security principles.

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PR created automatically by Jules for task 13422048934489669311 started by @yumin-chen

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