Move the browser suites into the repository

They lived in a scratch directory under /tmp, which was cleared overnight;
four of the five were simply gone. Whatever they were worth, they were
worth nothing kept there.

Rewritten against a shared lib.mjs. The old ones registered their users
through the sign-up form, which no longer exists — each suite now creates
a throwaway account through the admin API and deletes it afterwards, so a
run leaves the database as it found it. The previous generation left nine
accounts behind; those are gone too.

Three test hooks went into the app, each of which earns its place beyond
testing: aria-label on the note title (the sidebar search box is also a
text input, and a screen reader could not tell them apart either),
data-note-row on list rows, data-user on admin rows.

Two suites were flaky in ways worth naming, because both were the test
misreading the app rather than the app misbehaving:
- ticking a task then inserting a note link put the link inside the task
  list, since Control+End lands there. Verified against the server that
  the tick itself persists correctly; the suite now leaves the list first
  and asserts where the link ended up.
- the note-title lookup matched the sidebar's Trash entry, which wears the
  same emoji as a note row.

56 checks across five suites, all passing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

readme.md

@@ -309,6 +309,34 @@ bug they cover actually happened:
 - `hasPendingWrites` must cover the debounce window, not just requests in flight
 - v1 note bodies must migrate without losing task state or smuggling in markup
 
+### Browser suites
+
+The unit tests cover the data layer; these drive a real browser against a real
+server, because the failures that hurt most in this app were never visible in a
+unit test — a stale response overwriting fresh strokes, a note link surviving in
+memory but not through a reload.
+
+```bash
+docker compose -f docker-compose.dev.yml up -d --build   # must be running
+./e2e/run.sh                    # all suites
+./e2e/run.sh editor drawing     # only these
+```
+
+| Suite | Checks | What it holds down |
+| --- | --- | --- |
+| `admin` | 15 | no sign-up anywhere; `/api/admin/*` refused for non-admins even when called directly |
+| `editor` | 12 | tables, task lists, note links, backlinks — and that each survives a reload |
+| `search-attachments` | 12 | body-only matches, ranking, umlauts; images as blob URLs, not inline bytes |
+| `history` | 10 | a large deletion is snapshotted, restoring works, restoring is itself undoable |
+| `drawing` | 7 | strokes survive the poller, and match across four viewport widths |
+
+Each suite creates a throwaway account through the admin API and deletes it
+afterwards, so runs leave the database as they found it. They need an admin to
+do that with — `marc`/`geheim123` by default, override with `INKNOTE_ADMIN` and
+`INKNOTE_ADMIN_PASS`.
+
+Screenshots land in `e2e/shots/`, which is worth a look when a check fails.
+
 ### How the frontend is arranged
 
 `App.jsx` holds only *where the user is* — the open notebook, the open note, the