The extension now detects whether the local backend is running
automatically. If it is not running, the sidebar displays a
"Download Backend" button that downloads the companion server
package (12KB zip) directly from within the extension — no
external website visit required.

The backend package includes:
- START.bat for Windows (double-click to run)
- start.sh for Mac and Linux
- Pre-compiled server.js (no TypeScript or build step needed)
- Automatic dependency installation on first run
- Automatic Playwright browser download on first run

The sidebar also now polls every 5 seconds when the backend is
offline and switches to the ready state automatically as soon as
the backend starts — no manual refresh needed.


Replaced all inline onclick handlers with a CSP-compliant event
delegation pattern using data-action attributes.


Replaced all innerHTML assignments with DOMParser + replaceChildren()
for safe dynamic rendering.

• Minimum Firefox version: 140.0
• Backend runs on http://localhost:3001
• No data is sent to external servers
• All analysis is performed locally on the user's machine