feat: replace static Swagger UI server selector with dynamic client-side detection

- Update openapi.yaml to use single placeholder server URL
- Add swagger-server-detection.js to auto-detect current server URL from window.location
- Configure protocol, host, and port detection based on browser connection
- Fallback to placeholder URL if detection fails
- Include detection script in both app.js and index.js Swagger UI configurations
- /api/swagger.json endpoint returns static placeholder for external consumers

server/openapi.yaml

@@ -25,10 +25,8 @@ info:
     name: MIT
 
 servers:
-  - url: http://localhost:3001
-    description: Local development server
   - url: https://sofarr.example.com
-    description: Production server
+    description: sofarr API (auto-detected from current URL)
 
 tags:
   - name: Health