fix(e2e): bound the Playwright run and make a failed login say why (closes #161) (#165)

## What & why

#161 is really two defects, and the second one is why the first was undiagnosable.

**A wedged suite consumed the job, and took the post-mortem with it.** Nothing bounded the
Playwright run, so CI stopped the job mid-suite — and `if: always()` does not survive that. Run
739's job metadata shows every step after the e2e as a **0-second failure** stamped at the kill:

```
14 failure  09:48:17 -> 10:14:54  Self-service e2e (Playwright …)
15 failure  10:14:54 -> 10:14:54  verify-stack check summary       ← if: always()
16 failure  10:14:54 -> 10:14:54  e2e spec summary                 ← if: always()
17 failure  10:14:54 -> 10:14:54  Dump container logs on failure   ← if: failure()
18 failure  10:14:54 -> 10:14:54  Tear down                        ← if: always()
```

So the per-spec summary, the container-log dump and the teardown never ran, and the log lost
whatever the killed process had buffered — leaving the single `✘` line the issue was filed from.
`globalTimeout` now makes Playwright stop and *report*: the JSON report is written and those steps
still get their turn. (A `timeout-minutes` on the job would have reproduced the same failure, so
there isn't one.) The "~24-minute gap" is that kill, not necessarily a hang — note run 739 shows
`run_attempt: 2`, and `concurrency.cancel-in-progress` kills an in-flight run on any re-run or push.

**A login that never got its form ate the 90-second test timeout.** Playwright actions auto-wait
until the *test* timeout, not `expect.timeout` — so a portal that serves its page but never
bootstraps (its `config.json` fetch or the OIDC discovery behind `authorize()` failed; `main.ts`
only `console.error`s) spent 90s to report `locator.fill: Test timeout of 90000ms exceeded`: the
symptom, not the cause. That is catalogus.spec's 1.8 minutes. Both Keycloak forms are now asserted
visible first, with a 20s budget and a message naming the step that never happened.

Verified against a real blank-bootstrap portal — the beheer image served with a `config.json` that
is not JSON — which fails in **20.2s** with *"the Keycloak login form never appeared — the portal
did not reach Keycloak (check its config.json fetch and the OIDC discovery …)"*.

**And the summary now says why.** The per-spec table (#136) rendered a verdict icon and nothing
else, so even a surviving summary cost a log dive. Failing specs now carry their first error,
flattened for a table cell (ANSI stripped, newlines collapsed, `|` escaped, clipped) — shape
verified against a real @playwright/test 1.61 failing report, with a stdlib assert self-check on
`make unit`.

Closes #161

## Definition of Done

- [x] Linked Gitea issue (above).
- [x] Failing test committed before the implementation.
- [x] Implementation makes the test pass; refactor commit follows (login helper dedup).
- [x] Conventional Commits referencing the issue (`refs #161`).
- [ ] CI green — all Gitea Actions jobs.
- [x] `docker compose up` from a fresh clone reaches green health checks within 3 minutes (untouched).
- [x] Docs updated — `docs/runbooks/gitea-actions-gotchas.md` §9.
- [x] ADR — not needed: no boundary, dependency or coupling rule touched (test/CI infra only).
- [x] Demo note — not applicable: nothing user-visible.

## Notes for reviewers

**What this does not do: identify why the beheerder login failed that once.** The evidence to do
that was destroyed by defect 2, which is what this PR fixes. The suite ran green here five times
today (catalogus.spec 1.1–5.3s each) — but a local box is not the loaded CI runner, so that is weak
evidence and I am not claiming the flake is gone. What changes is that the next occurrence is
bounded and self-describing: it fails in 20s naming the failing step, the JSON report survives, and
the summary prints the error. Please keep #161 in mind rather than treating this as proof.

**Two follow-ups I did not pull into this PR:**
- *All four portals show a permanently blank page if their startup fetch fails* — `main.ts` does
  `fetch('config.json').then(bootstrap).catch(console.error)`, one shot, no UI and no recovery. That
  is a real product gap (the deliberately-broken portal above is exactly what a user would see) and
  wants its own slice, not a test-infra PR.
- `retries: 1` is untouched. CLAUDE.md §15 says flaky tests are fixed rather than retried, but
  removing retries while a real flake is unexplained would trade a rare red for a frequent one.
  Worth revisiting once #161 recurs (or doesn't) with the new diagnostics.

The login-helper rename (`medewerker-login.ts` → `keycloak-login.ts`, citizen logins routed through
`loginBurger`) is its own no-behaviour-change commit: the three citizen specs each duplicated the
same three-line login, so guarding the login path once meant routing them through it first.Reviewed-on: #165

infra/playwright-summary.py

@@ -7,10 +7,34 @@ redirects it into $GITHUB_STEP_SUMMARY. Stdlib only.
 """
 import json
 import os
+import re
 import sys
 
 STATUS_ICON = {"expected": "✅", "unexpected": "❌", "skipped": "⏭️", "flaky": "⚠️"}
 
+# A verdict alone still costs a log dive, and a killed or truncated job leaves no log to dive into
+# (#161) — so a failing spec carries its first error into the table. Playwright errors are multi-line
+# with a "Call log:", which a markdown table cell cannot hold, so they are flattened and clipped.
+ERROR_CLIP = 300
+
+
+def first_error(spec):
+    """The first error message across a spec's test results, flattened for one table cell."""
+    for test in spec.get("tests", []):
+        for result in test.get("results", []):
+            for error in result.get("errors", []):
+                message = (error.get("message") or "").strip()
+                if not message:
+                    continue
+                # Strip ANSI colour, collapse to one line, and keep it inside the cell.
+                message = re.sub(r"\x1b\[[0-9;]*m", "", message)
+                message = " ".join(message.split())
+                if len(message) > ERROR_CLIP:
+                    message = message[:ERROR_CLIP - 1].rstrip() + "…"
+                # `|` would end the cell early.
+                return message.replace("|", "\\|")
+    return ""
+
 
 def walk(suite, out):
     for spec in suite.get("specs", []):
@@ -22,7 +46,8 @@ def walk(suite, out):
                   else "expected" if spec.get("ok", False)
                   else "unexpected")
         out.append({"file": spec.get("file") or suite.get("file") or suite.get("title", ""),
-                    "title": spec.get("title", ""), "status": status})
+                    "title": spec.get("title", ""), "status": status,
+                    "error": first_error(spec) if status in ("unexpected", "flaky") else ""})
     for child in suite.get("suites", []):
         walk(child, out)
 
@@ -46,10 +71,17 @@ def main(path):
     if not specs:
         print("_No specs ran._")
         return 0
-    print("| Spec | Result |")
-    print("| ---- | :----: |")
-    for s in specs:
-        print(f"| {s['file']} › {s['title']} | {STATUS_ICON.get(s['status'], '❔')} |")
+    # The failure column only earns its width when something failed.
+    if any(s["error"] for s in specs):
+        print("| Spec | Result | Why |")
+        print("| ---- | :----: | --- |")
+        for s in specs:
+            print(f"| {s['file']} › {s['title']} | {STATUS_ICON.get(s['status'], '❔')} | {s['error']} |")
+    else:
+        print("| Spec | Result |")
+        print("| ---- | :----: |")
+        for s in specs:
+            print(f"| {s['file']} › {s['title']} | {STATUS_ICON.get(s['status'], '❔')} |")
     return 0