fix: use npm install instead of npm ci, change port to 3091

- npm ci requires a package-lock.json; use npm install --omit=dev instead
- Change all port references from 3001 to 3091 (3001 is occupied)
  - docker-compose.yml: ports, PORT env, healthcheck URL
  - Dockerfile: EXPOSE
  - .env.example: PORT default

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -4,16 +4,16 @@ services:
     container_name: bot-api
     restart: unless-stopped
     ports:
-      - "3001:3001"
+      - "3091:3091"
     volumes:
       - bot-data:/data
     environment:
-      - PORT=3001
+      - PORT=3091
       - DB_PATH=/data/bots.db
       - NODE_ENV=production
       - API_TOKEN=${API_TOKEN:-change-me-to-a-long-random-string}
     healthcheck:
-      test: ["CMD", "wget", "-qO-", "http://localhost:3001/api/v1/health"]
+      test: ["CMD", "wget", "-qO-", "http://localhost:3091/api/v1/health"]
       interval: 30s
       timeout: 5s
       retries: 3