feat(sprint-5): Phase 1 — Docker Compose full stack, CORS, Next.js upgrade

- Dockerfile.backend: multi-stage Java 21 build (eclipse-temurin)
- docker-compose.yml: PostgreSQL 16 + backend + frontend with health checks
- SecurityConfig: CORS for localhost:3000 frontend origin
- application-docker.properties: Docker profile with env vars
- Spring Boot Actuator health endpoint enabled
- Next.js upgraded 15.2.8 → 15.5.18 (security fixes)

docker-compose.yml

@@ -1,17 +1,15 @@
-version: '3.9'
-
 services:
   db:
     image: postgres:16-alpine
-    container_name: cannamanage-db-local
+    container_name: cannamanage-db
     environment:
       POSTGRES_DB: cannamanage
       POSTGRES_USER: cannamanage
-      POSTGRES_PASSWORD: dev_password_change_in_prod
+      POSTGRES_PASSWORD: cannamanage_dev
     ports:
       - "5432:5432"
     volumes:
-      - pgdata_local:/var/lib/postgresql/data
+      - pgdata:/var/lib/postgresql/data
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U cannamanage"]
       interval: 5s
@@ -21,19 +19,25 @@ services:
   backend:
     build:
       context: .
-      dockerfile: cannamanage-api/Dockerfile
+      dockerfile: Dockerfile.backend
     container_name: cannamanage-backend
     ports:
       - "8080:8080"
     environment:
-      - SPRING_DATASOURCE_URL=jdbc:postgresql://db:5432/cannamanage
-      - SPRING_DATASOURCE_USERNAME=cannamanage
-      - SPRING_DATASOURCE_PASSWORD=dev_password_change_in_prod
+      SPRING_PROFILES_ACTIVE: docker
+      SPRING_DATASOURCE_URL: jdbc:postgresql://db:5432/cannamanage
+      SPRING_DATASOURCE_USERNAME: cannamanage
+      SPRING_DATASOURCE_PASSWORD: cannamanage_dev
+      CANNAMANAGE_SECURITY_JWT_SECRET: docker-dev-secret-key-minimum-32-characters-long-for-hmac
     depends_on:
       db:
         condition: service_healthy
-    profiles:
-      - full
+    healthcheck:
+      test: ["CMD", "wget", "--spider", "-q", "http://localhost:8080/actuator/health"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 30s
 
   frontend:
     build:
@@ -43,13 +47,13 @@ services:
     ports:
       - "3000:3000"
     environment:
-      - BASE_URL=http://localhost:3000
-      - HOME_PATHNAME=/dashboards/analytics
-      - BACKEND_URL=http://backend:8080
+      NEXTAUTH_URL: http://localhost:3000
+      NEXTAUTH_SECRET: docker-dev-nextauth-secret-minimum-32chars
+      BACKEND_URL: http://backend:8080
+      AUTH_URL: http://localhost:3000
     depends_on:
-      - backend
-    profiles:
-      - full
+      backend:
+        condition: service_healthy
 
 volumes:
-  pgdata_local:
+  pgdata: