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>

.gitea/workflows/deploy.yml

@@ -129,8 +129,8 @@ jobs:
           echo "--- [4/5] 서비스 재시작 ---"
           sudo /usr/bin/systemctl restart taxbaik
 
-          echo "--- [5/5] 헬스 체크 (최대 120초) ---"
-          ATTEMPTS=40
+          echo "--- [5/5] 헬스 체크 (최대 60초) ---"
+          ATTEMPTS=20
           for i in \$(seq 1 \$ATTEMPTS); do
             STATUS=\$(curl -sf -o /dev/null -w '%{http_code}' http://127.0.0.1:5001/taxbaik/ 2>/dev/null || echo "000")
             if [ "\$STATUS" = "200" ]; then