fix: Optimize connection pool and enhance feedback count response handling

[asafchen-dig]

This PR addresses the rendering errors in the /api/clinic-feedback/count endpoint by implementing:

1. Connection Pool Optimization:

   • Configured HikariCP connection pool settings
   • Added retry mechanism for connection handling
   • Optimized pool size and timeout settings

2. Response Handling Improvements:

   • Updated FeedbackController to use ResponseEntity
   • Added proper error handling and logging
   • Implemented correct content type headers

These changes aim to:

• Reduce rendering errors (currently ~30% of requests)
• Improve response time consistency
• Enhance error handling and monitoring

Testing:

• Baseline trace ID for comparison: E13E84C2572AA4DB1BEE7FDD11A4459C
• Verified connection pool settings under load
• Tested error scenarios and response handling

Resolves the connection pool exhaustion and improper response handling issues identified in the feedback count endpoint.