feat: migrate server to spring boot

.vscode/settings.json

@@ -0,0 +1,4 @@
+{
+    "java.compile.nullAnalysis.mode": "automatic",
+    "java.configuration.updateBuildConfiguration": "interactive"
+}

CLAUDE.md

@@ -5,32 +5,101 @@ competency-based learning.
 
 ## Tech Stack
 
-Next.js 15 (App Router) · React 19 · TypeScript · shadcn/ui · Tailwind CSS 4 · PostgreSQL 16 ·
-Prisma (planned) · Zustand + TanStack Query · Vitest + Playwright (planned) · Docker
+**Frontend**: Next.js 15 (App Router) · React 19 · TypeScript · shadcn/ui · Tailwind CSS 4 · React Query · Axios
+
+**Backend**: Spring Boot 4.0 · Java 25 · PostgreSQL 16 · Flyway · JPA/Hibernate
+
+**Auth**: Keycloak 26.4 · OAuth2 · JWT
+
+**Deployment**: Docker Compose · Gradle
+
+## Architecture
+
+```
+Next.js Frontend (port 3000)
+├── React Components
+├── TanStack Query (server state)
+├── Axios API Client
+├── Keycloak Authentication
+└── TypeScript API Types
+
+Spring Boot Backend (port 8080)
+├── REST Controllers + OpenAPI
+├── Service Layer
+├── Spring Data JPA
+├── JPA Entities
+├── Flyway Migrations
+└── Spring Security + OAuth2
+
+Keycloak (port 8081)
+└── OAuth2/JWT Authentication
+
+PostgreSQL (port 5433)
+└── Application Database
+```
 
 ## Key Conventions
 
 - **Components**: PascalCase files, Server Components by default, `'use client'` only when needed
 - **Code Style**: Self-documenting code, minimal comments, rely on ESLint/Prettier
 - **Git**: Feature branches → PR → merge to main, multiple commits per branch OK
-- **Deployment**: Manual GitHub Actions triggers for staging/production
-- **Docker**: Use `./docker-manage.sh` for all operations (memo-dev, memo-staging, memo-prod)
+- **API**: RESTful endpoints, JWT authentication required
+- **Backend**: Use `server/server-manage.sh` for Spring Boot operations
+- **Frontend**: Standard Next.js development workflow
+
+## Quick Start
+
+**Backend:**
+```bash
+cd server
+./server-manage.sh up
+```
+
+**Frontend:**
+```bash
+npm run dev
+```
+
+**Access:**
+- Frontend: http://localhost:3000
+- API: http://localhost:8080
+- Swagger UI: http://localhost:8080/swagger-ui.html
+- Keycloak: http://localhost:8081 (admin/admin)
 
 ## AI Subagents
 
 Five specialized agents in `.claude/agents/`:
 
-1. **senior-architect** - Plans & orchestrates (NO implementation). Use proactively for new
-   features.
-2. **nextjs-expert** - App Router, routing, Server Actions
+1. **senior-architect** - Plans & orchestrates (NO implementation). Use proactively for new features.
+2. **nextjs-expert** - App Router, routing, React components
 3. **shadcn-expert** - UI components, Tailwind
-4. **database-expert** - PostgreSQL, Prisma, domain modeling
+4. **database-expert** - PostgreSQL, JPA, Spring Data
 5. **docker-expert** - Containers, deployment
 
 ## Workflow
 
-For new features: senior-architect analyzes → designs → creates plan → gets approval → orchestrates
-specialized agents
+For new features: senior-architect analyzes → designs → creates plan → gets approval → orchestrates specialized agents
+
+**Frontend Commands:**
+- `npm run dev` - Development server
+- `npm run build` - Production build
+- `npm run quality` - Type-check + lint + format
+
+**Backend Commands:**
+- `cd server && ./server-manage.sh up` - Start all services
+- `./server-manage.sh logs` - View logs
+- `./server-manage.sh build` - Build Spring Boot app
+- `./server-manage.sh test` - Run tests
+
+## Documentation
+
+- **QUICKSTART.md** - Step-by-step setup guide
+- **MIGRATION_COMPLETE.md** - Migration summary
+- **server/README.md** - Backend documentation
+- **SECURITY.md** - Security guidelines
+
+## Authentication
 
-Commands: `npm run quality` (type-check + lint + format), `npm run dev`,
-`./docker-manage.sh up development`
+All API requests require JWT token from Keycloak. Default users:
+- **Demo**: `demo@memo.local` / `demo` (USER role)
+- **Admin**: `admin@memo.local` / `admin` (ADMIN role)