docs: Add deployment and project documentation with unified env config

- Add DEPLOYMENT.md for 1Panel deployment guide with troubleshooting
- Add README.md with project architecture and quick start guide
- Update .gitignore to exclude development docs (openspec/, CLAUDE.md, etc.)
- Unify port configuration via .env (BACKEND_PORT, FRONTEND_PORT, MINIO_API_PORT, MINIO_CONSOLE_PORT)
- Update start-dev.sh and check-env.sh to read ports from .env

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

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

.env.example

@@ -152,3 +152,21 @@ REPORT_MAX_MESSAGES=200
 
 # MinIO path prefix for generated reports (default: reports)
 REPORT_STORAGE_PATH=reports
+
+# -----------------------------------------------------------------------------
+# Development Scripts Port Configuration
+# -----------------------------------------------------------------------------
+# These ports are used by start-dev.sh, start-prod.sh, and check-env.sh scripts.
+# They should match the actual service ports configured above.
+
+# Backend API port for scripts (default: 8000, should match PORT above)
+BACKEND_PORT=8000
+
+# Frontend development server port (default: 3000)
+FRONTEND_PORT=3000
+
+# MinIO S3 API port for Docker container (default: 9000)
+MINIO_API_PORT=9000
+
+# MinIO Web Console port for Docker container (default: 9001)
+MINIO_CONSOLE_PORT=9001