🧪 test: add JWT edge case scenarios with validation endpoint

- Add expired JWT token scenario

- Add wrong secret JWT token scenario

- Add malformed JWT token scenario

- Implement /api/v1/auth/validate endpoint

- Add JWT parsing and validation to BDD steps

Generated by Mistral Vibe.

Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

docker-compose.yml

@@ -0,0 +1,40 @@
+services:
+  postgres:
+    image: postgres:16-alpine
+    container_name: dance-lessons-coach-postgres
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: dance_lessons_coach
+    ports:
+      - "5432:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+    restart: unless-stopped
+
+  # Application service (for reference)
+  # app:
+  #   build: .
+  #   container_name: dance-lessons-coach-app
+  #   ports:
+  #     - "8080:8080"
+  #   environment:
+  #     - DLC_DATABASE_HOST=postgres
+  #     - DLC_DATABASE_PORT=5432
+  #     - DLC_DATABASE_USER=postgres
+  #     - DLC_DATABASE_PASSWORD=postgres
+  #     - DLC_DATABASE_NAME=dance_lessons_coach
+  #     - DLC_DATABASE_SSL_MODE=disable
+  #   depends_on:
+  #     postgres:
+  #       condition: service_healthy
+  #   restart: unless-stopped
+
+volumes:
+  postgres_data:
+    driver: local