Enhance graceful shutdown and logging for HTTP server

- Implemented graceful shutdown for the HTTP server, allowing for a controlled shutdown process with a timeout.
- Added logging for shutdown signals and server exit to improve traceability during application termination.
- Introduced IP blacklist configuration to enhance security by blocking specified IP addresses.
- Updated database cache configurations to allow dynamic adjustment via environment variables for better performance tuning.

pkg/spider/spider.go

@@ -357,7 +357,7 @@ func (s *Spider) queryRelayForEvents(
 			Authors: tag.NewFromBytesSlice(chunk...),
 			Since:   timestamp.FromUnix(startTime.Unix()),
 			Until:   timestamp.FromUnix(endTime.Unix()),
-			Limit:   func() *uint { l := uint(1000); return &l }(), // Limit to avoid overwhelming
+			Limit:   func() *uint { l := uint(500); return &l }(), // Limit to avoid overwhelming
 		}
 
 		// Subscribe to get events for this chunk