Initial project setup: Next.js frontend + .NET 9 backend

- Frontend: Next.js 16 + shadcn/ui + Tailwind CSS 4
- Backend: .NET 9 Web API with Npgsql health check
- Docker Compose for prod and dev environments
- Woodpecker CI pipeline for auto-deploy
- Health check endpoints for E2E testing

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

.gitignore

@@ -0,0 +1,25 @@
+# Frontend
+frontend/node_modules/
+frontend/.next/
+frontend/out/
+
+# Backend
+backend/src/*/bin/
+backend/src/*/obj/
+
+# Environment
+.env
+.env.local
+.env.production.local
+.env.development.local
+
+# IDE & Tools
+.vs/
+.vscode/
+.claude/
+*.swp
+*.swo
+
+# OS
+Thumbs.db
+.DS_Store