feat: initial LexAI Chrome extension scaffold

- WXT + React 18 + TypeScript setup
- Background service worker (LLM API proxy)
- Content script (floating toolbar + text selection)
- Options page (provider/model/API key config)
- Popup UI
- Gitea Actions workflows (CI, preview, release)
- Vitest unit tests + Playwright E2E setup
- Supports: OpenAI, Anthropic, Groq, OpenRouter

README.md

@@ -0,0 +1,42 @@
+# ⚡ LexAI — AI Writing Assistant
+
+A Grammarly-like Chrome Extension powered by **your own LLM API key**. No monthly subscription. Full control.
+
+## Features (Roadmap)
+- ✅ Grammar & spelling correction
+- ✅ Rephrase / rewrite text
+- ✅ Shorten or expand text
+- 🔜 Tone suggestions
+- 🔜 Autocomplete
+- 🔜 Custom style profiles
+
+## Supported LLM Providers
+- **OpenAI** (GPT-4o, GPT-4o-mini)
+- **Anthropic** (Claude 3.5 Haiku, Sonnet)
+- **Groq** (free tier — fast!)
+- **OpenRouter** (100+ models)
+
+## Tech Stack
+- WXT + React 18 + TypeScript
+- Tailwind CSS
+- Zustand (state)
+- Manifest V3
+
+## Development
+
+```bash
+npm install
+npm run dev      # Dev mode with hot reload
+npm run build    # Production build
+npm run zip      # Package for Chrome Web Store
+npm test         # Run unit tests
+```
+
+## Load in Chrome
+1. Run `npm run build`
+2. Open Chrome → `chrome://extensions`
+3. Enable **Developer Mode**
+4. Click **Load unpacked** → select `.output/chrome-mv3`
+
+## Project Management
+Plane: LEXAI project → https://plane-pro.juankibin.space