Re-establish a baseline of coverage (Phase 0 removed all tests with Dunbar)
and guard the upcoming App Router migration: the route URLs are stable across
that migration, so this spec must stay green before and after.

- tests/e2e/smoke.spec.ts: visits all 14 public routes, asserts the document
  responds < 400, renders non-empty content, and throws no genuine uncaught
  exception. Tolerates dev-only React hydration warnings and third-party embed
  noise (would otherwise be flaky); caps the settle wait so embed-heavy pages
  don't hang.
- Fix a pre-existing Playwright version split: @playwright/test (1.57.0 via
  ^1.55.0) and playwright (1.58.2) resolved to two copies, breaking the runner
  ("test() not expected here"). Pin both to 1.60.0.

All 14 routes green (~55s, Node 20). Surfaced for later: a real /cosmicfest
dev-mode hydration mismatch (task #7), a legacyBehavior next/link deprecation,
and a next/head stylesheet warning — all to address in the App Router pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>