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>

README.md

@@ -151,10 +151,17 @@ Private / personal use.
 ## Development
 
 ```bash
-npm run test:run   # all tests
+npm run test:run   # all unit and component tests
+npm run test:e2e   # real-browser tests (Playwright, in your installed Chrome)
 npm run lint       # ESLint (errors fail; warnings are advice)
 ```
 
+The browser tests (`e2e/`) build the app, run it on port 3101 with an empty throwaway database (your real studies are never
+touched), make an account, and click through the main flows: writing notes and the paste check, the daily five minutes and weekly
+recall, comparing translations (Bible text is faked, so no internet is needed), and presenting on two screens. They use the
+Chrome already on the computer, so there is no browser to download; install Chrome, or change `channel` in `playwright.config.js`
+and run `npx playwright install` to use Playwright's own browser.
+
 Who can sign up: the administrator (the `ADMIN_EMAIL` account) chooses Open, Invite only or Closed under Admin → Sign-ups, and makes single-use invite links there. The very first account can always be created.
 
 Verse of the day push: with `IQBIBLE_API_KEY` set, each person can turn on a daily verse notification in Settings → Reading reminders (it goes to the same ntfy topic).