feat: add Docker support and logging enhancements

- Introduced Dockerfile and .dockerignore for containerization of the backend service.
- Added logging configuration with support for daily rolling logs and customizable log levels.
- Enhanced the server to utilize structured logging with zap, including detailed request and error logging.
- Updated configuration to include logging parameters and proxy settings.
- Implemented tests for logging configuration and proxy settings.

backend/.dockerignore

@@ -0,0 +1,13 @@
+.git
+.gitignore
+.claude
+
+docs
+
+cmd/server.exe
+*.log
+*.out
+
+config.json
+
+**/*_test.go