test: F4.9 the editor by finger in Chromium and on an iPad upright and on its side

The touch test runs in Chromium on the desktop and in WebKit as an iPad
(810x1080 and 1080x810): the acceptance of F4 as a script ("zwei
Rechnernetze" built anew by finger, set up and pinged across), two fingers
zoom the surface and never the page (M7, without a frame), every action
without a right click, every target at least 44 px. Real gestures: CDP in
Chromium, WebKit's own Input.dispatchTouchEvent through Playwright's
in-process connection (Playwright pinned to 1.62.1). A dragged finger holds
still before it is lifted, or Chromium takes it for a fling.

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

README.md

@@ -41,7 +41,7 @@ Plan und Entscheidungen: `knowledge/plans/FILIUS_WEB_PLAN.md` im Dashboard.
 npm install
 npm run hooks      # Sprachprüfung vor jedem Commit (braucht das Dashboard drumherum)
 npm run check      # Typprüfung + Tests
-npm run test:browser  # Tests im echten Browser (Playwright, Chromium aus dem Cache)
+npm run test:browser  # Tests im echten Browser (Playwright: Chromium; der Touch-Test auch in WebKit als iPad hoch und quer)
 ```
 
 Code, Kommentare und Testnamen sind englisch; sichtbare Texte stehen hinter