ci: run the checks that only ran on a laptop; mobile in CI; retries 0

CI ran Playwright (chromium-desktop) + the dependency audit and nothing else. cargo test,
clippy, the frontend vitest suite, svelte-check and the e2e typecheck were all green on a
developer's machine and gated NOTHING.

  checks.yml (new): cargo test (with a Postgres service; --test-threads bounded so the
    sqlx per-test DBs can't exhaust connections) + clippy; vitest + svelte-check; e2e tsc.
  e2e.yml: also run the chromium-mobile project — 22 tests (focus traps, touch targets,
    safe-area, viewport reflow) that never ran in CI on a phone-first app.
  playwright.config: widen webkit-iphone beyond @smoke (2 specs) to the core guest journeys
    (auth/upload/feed) — iOS Safari is the PRIMARY browser here; and retries 2 → 0.

retries:0 is deliberate and against the usual advice: this repo's real bugs are races, a
race is indistinguishable from a flake from outside, and a retry resolves that ambiguity
toward "flake" every time — it took a real 3%-flaky product bug from 1-in-33 to 1-in-37000,
green. A flake here is a bug report.

Not gated: cargo fmt (the tree has never been rustfmt'd — a 112-file reformat would bury
every real diff; do it separately). WebKit widening is unverified locally (needs libavif16
via sudo), so its first CI run may surface real iOS bugs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/e2e.yml

@@ -46,6 +46,14 @@ jobs:
         working-directory: ./e2e
         run: npm run test:e2e -- --project=chromium-desktop
 
+      # 09-mobile is `testIgnore`d on chromium-desktop (it needs hasTouch + a phone viewport), so
+      # running only that project left 22 tests — focus traps, touch targets, safe-area insets,
+      # viewport reflow, upload-cancel — never executing in CI. On a phone-first event app, where
+      # essentially every real guest is on a phone, that was the wrong half of the suite to skip.
+      - name: Run E2E tests (mobile)
+        working-directory: ./e2e
+        run: npm run test:e2e -- --project=chromium-mobile
+
       - name: Upload Playwright report
         if: failure()
         uses: actions/upload-artifact@v4