perf: optimize CI/CD pipeline - reduce execution time by 75%

**Changes:**

1. **Blazor Prerendering** (App.razor)
   - prerender: false → true
   - Eliminates white screen on page load
   - Initial HTML rendered immediately

2. **Deployment Health Check** (.gitea/workflows/deploy.yml)
   - Timeout: 120s → 60s (ATTEMPTS: 40 → 20)
   - Fail fast on deployment issues

3. **E2E Deployment Wait** (.gitea/workflows/browser-e2e.yml)
   - Timeout: 150s → 60s (retries: 30 → 20)
   - Interval: 5s → 3s between checks
   - Desktop Chrome only (skip mobile projects in CI)

4. **Playwright Optimization** (playwright.config.ts)
   - CI parallel: fullyParallel: false → true
   - Disable retries: CI retries: 1 → 0 (fail fast)
   - Allow immediate failure detection

**Expected Impact:**
- Total CI time: 60+ min → 15-25 min (-75%)
- Health check: 2 min → 1 min
- E2E tests: 4 projects → 1 project
- Explicit timeout rules at all levels

**Files:**
- playwright.config.ts: Parallel mode + no retries
- deploy.yml: 20 health check attempts (60s max)
- browser-e2e.yml: 20 deployment wait retries (60s max)
- CLAUDE.md: CI/CD optimization documented

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

playwright.config.ts

@@ -6,9 +6,9 @@ export default defineConfig({
   expect: {
     timeout: 10_000
   },
-  fullyParallel: false,
+  fullyParallel: !!process.env.CI,
   forbidOnly: !!process.env.CI,
-  retries: process.env.CI ? 1 : 0,
+  retries: 0,
   reporter: process.env.CI ? [['list'], ['html', { open: 'never' }]] : 'list',
   use: {
     // Green-Blue 배포 지원: