refactor: migrate extension to TypeScript and add Material-UI components

hero_vault_extension/README.md

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+# SAL Modular Cryptographic Browser Extension
+
+A modern, secure browser extension for interacting with the SAL modular Rust cryptographic stack, enabling key management, cryptographic operations, and secure Rhai script execution.
+
+## Features
+
+### Session & Key Management
+- Create and unlock encrypted keyspaces with password protection
+- Create, select, and manage multiple keypairs (Ed25519, Secp256k1)
+- Clear session state visualization and management
+
+### Cryptographic Operations
+- Sign and verify messages using selected keypair
+- Encrypt and decrypt messages using asymmetric cryptography
+- Support for symmetric encryption using password-derived keys
+
+### Scripting (Rhai)
+- Execute Rhai scripts securely within the extension
+- Explicit user approval for all script executions
+- Script history and audit trail
+
+### WebSocket Integration
+- Connect to WebSocket servers using keypair's public key
+- Receive, review, and approve/reject incoming scripts
+- Support for both local and remote script execution
+
+### Security
+- Dark mode UI with modern, responsive design
+- Session auto-lock after configurable inactivity period
+- Explicit user approval for all sensitive operations
+- No persistent storage of passwords or private keys in plaintext
+
+## Architecture
+
+The extension is built with a modern tech stack:
+
+- **Frontend**: React with TypeScript, Material-UI
+- **State Management**: Zustand
+- **Backend**: WebAssembly (WASM) modules compiled from Rust
+- **Storage**: Chrome extension storage API with encryption
+- **Networking**: WebSocket for server communication
+
+## Development Setup
+
+1. Install dependencies:
+   ```
+   cd sal_extension
+   npm install
+   ```
+
+2. Build the extension:
+   ```
+   npm run build
+   ```
+
+3. Load the extension in Chrome/Edge:
+   - Navigate to `chrome://extensions/`
+   - Enable "Developer mode"
+   - Click "Load unpacked" and select the `dist` directory
+
+4. For development with hot-reload:
+   ```
+   npm run watch
+   ```
+
+## Integration with WASM
+
+The extension uses WebAssembly modules compiled from Rust to perform cryptographic operations securely. The WASM modules are loaded in the extension's background script and provide a secure API for the frontend.
+
+Key WASM functions exposed:
+- `init_session` - Unlock a keyspace with password
+- `create_keyspace` - Create a new keyspace
+- `add_keypair` - Create a new keypair
+- `select_keypair` - Select a keypair for use
+- `sign` - Sign a message with the selected keypair
+- `run_rhai` - Execute a Rhai script securely
+
+## Security Considerations
+
+- The extension follows the principle of least privilege
+- All sensitive operations require explicit user approval
+- Passwords are never stored persistently, only kept in memory during an active session
+- Session state is automatically cleared when the extension is locked
+- WebSocket connections are authenticated using the user's public key
+
+## License
+
+[MIT License](LICENSE)