Real-browser tests (Playwright) and housekeeping

- npm run test:e2e builds the app, runs it on port 3101 with an empty throwaway
  database and drives Chrome (the installed one; no browser download) through
  notes and the paste check, the daily five minutes and weekly recall,
  translation compare (Bible text faked), and two-screen presenting.
- Vitest skips e2e/; ESLint knows the e2e folder and playwright.config.js.
- .gitignore: the local demo video, Playwright output and sign-in file.
- README and TODO describe the browser tests and what CI still needs.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

vite.config.js

@@ -18,6 +18,7 @@ export default defineConfig({
     },
   },
   test: {
+    exclude: ['e2e/**', 'node_modules/**', 'dist/**'], // e2e/ holds the Playwright browser tests (npm run test:e2e)
     environment: 'jsdom',
     environmentOptions: {
       jsdom: { url: 'http://localhost:3000/' },