WP-00: project skeleton with three-level test harness

Cargo workspace (domain, application, infrastructure, api), axum health endpoint
with SPA fallback, Vue 3 + Tailwind frontend, Vitest, Playwright, Makefile,
Gitea Actions CI and README.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

frontend/playwright.config.ts

@@ -0,0 +1,30 @@
+import { defineConfig } from '@playwright/test'
+
+// UI tests run against the Vite dev server, which proxies /api to a backend started
+// with a throw-away SQLite database and a known bootstrap admin.
+export default defineConfig({
+  testDir: './e2e',
+  timeout: 30_000,
+  fullyParallel: false,
+  workers: 1,
+  reporter: 'list',
+  use: { baseURL: 'http://127.0.0.1:5173', trace: 'retain-on-failure' },
+  webServer: [
+    {
+      command: 'cargo run -q -p api',
+      cwd: '../backend',
+      url: 'http://127.0.0.1:8080/healthz',
+      reuseExistingServer: false,
+      timeout: 180_000,
+      env: {
+        DATABASE_URL: 'sqlite::memory:',
+        JWT_SECRET: 'e2e-test-secret-do-not-use-in-production',
+        BOOTSTRAP_ADMIN_EMAIL: 'admin@example.com',
+        BOOTSTRAP_ADMIN_PASSWORD: 'admin-password-123',
+        BIND: '127.0.0.1:8080',
+        RUST_LOG: 'warn',
+      },
+    },
+    { command: 'npm run dev', url: 'http://127.0.0.1:5173', reuseExistingServer: false, timeout: 60_000 },
+  ],
+})