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

entrypoints/popup/Popup.tsx

@@ -0,0 +1,65 @@
+import React, { useEffect, useState } from 'react';
+import { createRoot } from 'react-dom/client';
+
+function Popup() {
+  const [configured, setConfigured] = useState(false);
+  const [provider, setProvider] = useState('');
+  const [model, setModel] = useState('');
+
+  useEffect(() => {
+    chrome.storage.local.get(['provider', 'apiKey', 'model'], (result) => {
+      if (result.apiKey) {
+        setConfigured(true);
+        setProvider(result.provider || 'openai');
+        setModel(result.model || '');
+      }
+    });
+  }, []);
+
+  const openSettings = () => chrome.runtime.openOptionsPage();
+
+  return (
+    <div style={{ padding: 16, fontFamily: 'system-ui, sans-serif', color: '#1e1e2e' }}>
+      <div style={{ display: 'flex', alignItems: 'center', gap: 8, marginBottom: 12 }}>
+        <span style={{ fontSize: 20 }}>⚡</span>
+        <span style={{ fontSize: 16, fontWeight: 700 }}>LexAI</span>
+      </div>
+
+      {configured ? (
+        <div>
+          <div style={{ background: '#e8f5e9', borderRadius: 8, padding: '8px 12px', marginBottom: 12 }}>
+            <div style={{ fontSize: 12, color: '#388e3c', fontWeight: 600 }}>✓ Active</div>
+            <div style={{ fontSize: 12, color: '#555', marginTop: 2 }}>{provider} / {model}</div>
+          </div>
+          <p style={{ fontSize: 12, color: '#6c6f85', marginBottom: 12 }}>
+            Select any text on a webpage to see LexAI options appear.
+          </p>
+        </div>
+      ) : (
+        <div style={{ background: '#fff3e0', borderRadius: 8, padding: '8px 12px', marginBottom: 12 }}>
+          <div style={{ fontSize: 12, color: '#e65100', fontWeight: 600 }}>⚠ Setup Required</div>
+          <div style={{ fontSize: 12, color: '#555', marginTop: 2 }}>Add your API key to get started</div>
+        </div>
+      )}
+
+      <button
+        onClick={openSettings}
+        style={{
+          width: '100%',
+          background: '#89b4fa',
+          color: '#1e1e2e',
+          border: 'none',
+          borderRadius: 8,
+          padding: '8px',
+          fontSize: 13,
+          fontWeight: 600,
+          cursor: 'pointer',
+        }}
+      >
+        ⚙ Open Settings
+      </button>
+    </div>
+  );
+}
+
+createRoot(document.getElementById('app')!).render(<Popup />);