Refactor golangci-lint configuration and improve error handling

- Updated .golangci.yml to enable default linters and refine suppression rules, enhancing code quality visibility.
- Improved error handling in cmd/root.go by explicitly discarding low-value error messages during fatal exits for consistency with errcheck posture.
- Added best-effort error handling in various locations across the codebase, ensuring that non-critical errors are logged without affecting overall functionality.
- Introduced a new writeMetricsText function to streamline metrics output, improving code clarity and maintainability.

cmd/root.go

@@ -72,7 +72,7 @@ var rootCmd = &cobra.Command{
 						Err(err).
 						Str("config_path", configPath).
 						Msg("Failed to create default configuration")
-					fmt.Fprintf(os.Stderr, "Error: Failed to create default config at %s: %v\n", configPath, err)
+					_, _ = fmt.Fprintf(os.Stderr, "Error: Failed to create default config at %s: %v\n", configPath, err) // explicit discard for fatal stdio path (consistent with errcheck posture; low-value on exit)
 					os.Exit(1)
 				}
 
@@ -88,7 +88,7 @@ var rootCmd = &cobra.Command{
 					Err(err).
 					Str("config_path", configPath).
 					Msg("Failed to load configuration")
-				fmt.Fprintf(os.Stderr, "Error: Failed to load configuration from %s: %v\n", configPath, err)
+				_, _ = fmt.Fprintf(os.Stderr, "Error: Failed to load configuration from %s: %v\n", configPath, err) // explicit discard for fatal stdio path (consistent with errcheck posture; low-value on exit)
 				os.Exit(1)
 			}
 		}
@@ -113,7 +113,7 @@ var rootCmd = &cobra.Command{
 			logger.Logger.Error().
 				Err(err).
 				Msg("Configuration validation failed")
-			fmt.Fprintf(os.Stderr, "Error: Invalid configuration: %v. Please fix the config file and try again.\n", err)
+			_, _ = fmt.Fprintf(os.Stderr, "Error: Invalid configuration: %v. Please fix the config file and try again.\n", err) // explicit discard for fatal stdio path (consistent with errcheck posture; low-value on exit)
 			os.Exit(1)
 		}
 
@@ -134,7 +134,7 @@ var rootCmd = &cobra.Command{
 			logger.Logger.Error().
 				Err(err).
 				Msg("Failed to initialize steamcache")
-			fmt.Fprintf(os.Stderr, "Error: Failed to initialize steamcache: %v. Check sizes in config.\n", err)
+			_, _ = fmt.Fprintf(os.Stderr, "Error: Failed to initialize steamcache: %v. Check sizes in config.\n", err) // explicit discard for fatal stdio path (consistent with errcheck posture; low-value on exit)
 			os.Exit(1)
 		}
 
@@ -143,7 +143,7 @@ var rootCmd = &cobra.Command{
 
 		if err := sc.Run(); err != nil {
 			logger.Logger.Error().Err(err).Msg("steamcache2 Run failed")
-			fmt.Fprintf(os.Stderr, "Error: steamcache2 run error: %v\n", err)
+			_, _ = fmt.Fprintf(os.Stderr, "Error: steamcache2 run error: %v\n", err) // explicit discard for fatal stdio path (consistent with errcheck posture; low-value on exit)
 			os.Exit(1)
 		}