phase 2: ui testing infrastructure

Vitest + @testing-library/jest-dom matchers wired through tests/setup.ts.
Playwright with four projects: chromium-desktop, webkit-desktop,
chromium-mobile-iphone-13, chromium-mobile-pixel-5; traces and
screenshots retained on failure.

.gitea/workflows/ui-test.yaml runs Tier 1 on every push and pull
request: monorepo Go service tests (backend with -p 1 to dodge
testcontainer contention; gateway, game, every pkg/<name> module),
pnpm install --frozen-lockfile, playwright install --with-deps,
pnpm test, pnpm exec playwright test. Uploads playwright-report
and test-results on failure. Integration suite stays gated behind
make -C integration integration; deprecated client/ excluded.

.gitea/workflows/ui-release.yaml mirrors Tier 1 on v* tag push and
keeps commented placeholders for visual regression (Phase 33) and
macOS iOS smoke (Phase 32).

ui/docs/testing.md documents both tiers and the local invocations
that mirror what CI runs. ui/PLAN.md Phase 2 marked done; Phase 3
gains a bullet to extend the go test command with ./ui/core/...;
Phase 36 has the renamed release workflow path.

tools/local-ci/ ships a self-contained docker-compose for verifying
workflows against a local Gitea + arm64 act_runner before pushing
to a real instance.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/tests/e2e/landing.spec.ts

@@ -0,0 +1,8 @@
+import { expect, test } from "@playwright/test";
+
+test("landing page renders the version string", async ({ page }) => {
+	await page.goto("/");
+	const footer = page.getByTestId("app-version");
+	await expect(footer).toBeVisible();
+	await expect(footer).toContainText(/version\s+\S+/);
+});