Add persistent PostgreSQL stack and SQLite migration

docker-compose.yml

@@ -1,15 +1,45 @@
 services:
+  db:
+    image: postgres:16-alpine
+    container_name: telco-db
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: telco
+      POSTGRES_USER: telco
+      POSTGRES_PASSWORD: ${TELCO_DB_PASSWORD:-telco}
+    volumes:
+      - telco-db-data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U telco -d telco"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
   telcoportal:
     build:
       context: ./TelcoPortal-source
       dockerfile: Dockerfile
     container_name: telcoportal
     restart: unless-stopped
+    depends_on:
+      db:
+        condition: service_healthy
     ports:
       - "8092:8000"
     volumes:
-      # Host-side folder - keeps the SQLite database across rebuilds/updates, and makes it
-      # easy to back up (just copy/zip this folder).
-      - ./TelcoPortal-data:/app/data
+      - telco-app-data:/app/data
+      # Read-only source for the automatic first-run SQLite import.
+      - ./data:/app/legacy-data:ro
     environment:
-      - TELCO_DATA_DIR=/app/data
+      TELCO_DATA_DIR: /app/data
+      TELCO_DB_HOST: db
+      TELCO_DB_PORT: 5432
+      TELCO_DB_NAME: telco
+      TELCO_DB_USER: telco
+      TELCO_DB_PASSWORD: ${TELCO_DB_PASSWORD:-telco}
+      TELCO_LEGACY_SQLITE_PATH: /app/legacy-data/telco.db
+    command: ["sh", "-c", "python migrate_sqlite.py && exec gunicorn --bind 0.0.0.0:8000 --workers 2 app:app"]
+
+volumes:
+  telco-db-data:
+  telco-app-data: