updated 3 tier structure

docker-compose.dev.yml

@@ -0,0 +1,53 @@
+# Dev-sidecar compose: app container + PostgreSQL sidecar.
+# Used by .devcontainer/devcontainer.json via dockerComposeFile.
+
+services:
+  app:
+    build:
+      context: .
+      dockerfile: .devcontainer/Dockerfile
+    restart: "no"
+    ports:
+      - "8000:8000"   # FastAPI
+      - "4200:4200"   # Angular dev server
+    environment:
+      KMTN_DATABASE_URL: postgresql+asyncpg://postgres:postgres@db:5432/kmountain
+      KMTN_CORS_ORIGINS: '["http://localhost:4200"]'
+    volumes:
+      - ..:/workspaces/web_app:cached
+      - node_modules:/workspaces/web_app/node_modules
+      - backend_venv:/app/.venv
+    depends_on:
+      db:
+        condition: service_healthy
+    command: >
+      sh -c "
+        pip install -r backend/requirements.txt &&
+        cd backend &&
+        uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload &
+        cd /workspaces/web_app &&
+        npm install &&
+        npx ng serve --host 0.0.0.0 --port 4200
+      "
+
+  db:
+    image: docker.io/library/postgres:16-alpine
+    restart: "no"
+    environment:
+      POSTGRES_DB: kmountain
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    ports:
+      - "5432:5432"
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  pgdata:
+  node_modules:
+  backend_venv: