Playwright E2E test harness with scaffolded auth flow + per-resource happy paths

[MUKE-coder]

Problem

E2E tests are crucial but painful to set up. Most teams ship without them, then a regression breaks billing in production. "Write E2E tests" lives at the bottom of every backlog because the setup cost is high.

Proposal

`grit init` produces a working E2E test suite:

• Playwright configured for desktop / web / admin clients
• Login fixture seeded automatically (uses the seed admin user)
• Per-resource happy-path tests generated alongside the resource:
  • List page loads
  • New resource via drawer form succeeds
  • Edit succeeds
  • Delete + restore (Soft deletes everywhere with restore UI + retention policy #45) round-trip
  • Search + filter chips (<FilterChips> primitive for inline status / type filter rows #26) work
• Test runs against a throwaway Postgres (Docker) — no shared state
• CI integration with GitHub Actions ships in the template

`grit generate resource` adds a corresponding `.e2e.spec.ts` file.

Why this is differentiating

Grit apps shipped with E2E coverage from line one are categorically more reliable than apps where E2E is bolted on later. Reliability is a sales argument.

Acceptance

• A fresh `grit init` repo runs `pnpm test:e2e` green out of the box
• Adding a new resource adds new passing E2E tests automatically
• CI runs the full suite in <5 min

[MUKE-coder]

Partial: every monorepo scaffold already ships playwright.config.ts + e2e/auth.spec.ts + e2e/admin.spec.ts with a working scaffolded auth flow test. Remaining: the resource generator emitting per-resource happy-path E2E tests (e.g. grit generate resource Building → e2e/building.spec.ts covering list/create/edit/delete via the admin UI). Leaving open for that delta.