refactor(api): restructured API for type safety, maintainability and docs generation

- These changes makes the API incombatible with previous versions
- Added new types for error handling, success responses, and health checks.
- Updated health check logic to utilize the new types for better clarity and structure.
- Refactored existing handlers to improve response consistency and error handling.
- Updated Makefile to include a new target for generating API types from Swagger.
- Updated "new agent" API to respond an encrypted cert pair

internal/config/types/config.go

@@ -45,7 +45,7 @@ type (
 	RouteProviderListResponse struct {
 		ShortName string `json:"short_name"`
 		FullName  string `json:"full_name"`
-	}
+	} // @name RouteProvider
 	ConfigInstance interface {
 		Value() *Config
 		Reload() gperr.Error