feat(extension): browser extension for Chrome/Edge/Firefox + CI + v0.8.0

Adds a WXT-based browser extension that replaces manual JS snippet
injection for AI-driven browser testing. The extension auto-connects
to the Muyue server via WebSocket on every page, using the exact
same protocol as the existing snippet — zero backend changes needed.

- Chrome/Edge (MV3) + Firefox (MV2) from single codebase via WXT
- Content script: auto-connect WS, console capture, URL tracking, RPC
- Background service worker: token management, screenshots, badge
- Popup + side panel with server status, sessions, URL config
- CI workflows: build extension, attach .zip to releases
- Makefile targets: ext, ext-chrome, ext-firefox, ext-zip
- Version bumped to 0.8.0

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

README.md

@@ -17,6 +17,45 @@ AI-powered development environment assistant by **La Légion de Muyue**.
 - **i18n** — Full FR/EN support with keyboard layout awareness (AZERTY, QWERTY, QWERTZ)
 - **4 themes** — Cyberpunk Red, Cyberpunk Pink, Midnight Blue, Matrix Green
 
+## Browser Extension
+
+Muyue ships a **browser extension** (Chrome, Edge, Firefox) that replaces the manual snippet injection for the Tests tab:
+
+- **Auto-injects** the Muyue test client on every HTTP/HTTPS page — no more copy-paste
+- **Captures console** errors/warnings in real-time
+- **Native screenshots** via `captureVisibleTab` — pixel-perfect
+- **Side Panel** (Chrome/Edge) and **Sidebar** (Firefox) for status monitoring
+- **Badge** shows active session count or server status
+
+### Install from source
+
+```bash
+cd extension
+npm install
+npm run build          # Chrome/Edge → .output/chrome-mv3/
+npm run build:firefox  # Firefox → .output/firefox-mv2/
+```
+
+Then load the extension:
+- **Chrome/Edge**: `chrome://extensions` → Developer mode → Load unpacked → select `extension/.output/chrome-mv3/`
+- **Firefox**: `about:debugging#/runtime/this-firefox` → Load temporary Add-on → select any file in `extension/.output/firefox-mv2/`
+
+### Download pre-built
+
+Extension `.zip` files are attached to every [release](https://gitea.legion-muyue.fr/Muyue/MuyueWorkspace/releases):
+
+- `muyue-extension-*-chrome.zip` — Chrome Web Store ready
+- `muyue-extension-*-firefox.zip` — Firefox Add-ons ready
+- `muyue-extension-*-sources.zip` — Required source for Firefox Add-ons review
+
+### Development
+
+```bash
+cd extension
+npm run dev            # Chrome dev mode with HMR
+npm run dev -- --browser firefox  # Firefox dev mode
+```
+
 ## Tech Stack
 
 | Layer | Technology |
@@ -186,6 +225,10 @@ The Go backend serves 15 REST endpoints under `/api/`:
 │   │   ├── styles/global.css  # Full CSS theme system
 │   │   └── themes/index.js    # 4 themes with CSS variable injection
 │   └── vite.config.js         # Vite + dev proxy to :8095
+├── extension/                 # Browser extension (WXT, Chrome/Edge/Firefox)
+│   ├── src/entrypoints/       # background, content, popup, sidepanel
+│   ├── src/lib/               # config, page-rpc (shared logic)
+│   └── src/styles/            # cyberpunk panel CSS
 ├── .gitea/workflows/          # CI/CD (PR check, beta, stable)
 └── Makefile                   # build, test, lint, cross-compile
 ```