fix: Complete CI/CD testing infrastructure setup

**Environment Variables:**
- Fixed docker-compose.ci.yml to use correct environment variable names:
  - SURREALDB_JWT_SECRET (not SURREAL_JWT_SECRET)
  - GOOGLE_GENERATIVE_AI_API_KEY (not GOOGLE_API_KEY)
- Updated Gitea Actions workflow to match correct variable names

**Docker Configuration:**
- Removed SurrealDB health check (minimal scratch image lacks utilities)
- Added 10-second sleep before Next.js starts to wait for SurrealDB
- Updated magnitude service to run as root user for npm global installs
- Added xvfb-run to magnitude command for headless browser testing
- Updated Playwright Docker image from v1.49.1 to v1.56.1 in both files
- Added named volume for node_modules to persist installations

**Test Configuration:**
- Updated magnitude.config.ts to use Claude Sonnet 4.5 (20250929)
- Added headless: true to playwright.config.ts

**Testing:**
- CI test script (./scripts/test-ci-locally.sh) now works correctly
- All services start properly: SurrealDB → Next.js → Magnitude
- Playwright launches successfully in headless mode with xvfb-run

Note: Users need to ensure .env contains:
- ATPROTO_CLIENT_ID
- ATPROTO_REDIRECT_URI
- SURREALDB_JWT_SECRET
- GOOGLE_GENERATIVE_AI_API_KEY
- ANTHROPIC_API_KEY

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

docker-compose.yml

@@ -34,7 +34,7 @@ services:
       - surrealdb
 
   playwright:
-    image: mcr.microsoft.com/playwright:v1.49.1-noble
+    image: mcr.microsoft.com/playwright:v1.56.1-noble
     working_dir: /home/pwuser/app
     user: pwuser
     network_mode: host