Migrate DeepDrftContext from SQLite to PostgreSQL; add docker-compose for local Postgres 17

docker-compose.yml

@@ -0,0 +1,14 @@
+services:
+  postgres:
+    image: postgres:17
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: deepdrft_dev
+    ports:
+      - "5432:5432"
+    volumes:
+      - deepdrft_postgres:/var/lib/postgresql/data
+
+volumes:
+  deepdrft_postgres: