Fix SwiftLint and SwiftFormat violations

- Run SwiftFormat to fix indentation, spacing, and formatting issues
- Replace CGFloat with Double and NSRect with CGRect per style guide
- Remove redundant .center alignment specifications
- Remove unnecessary @available checks for satisfied deployment targets
- Fix closure brace indentation for consistency
- Disable closure_end_indentation rule to resolve SwiftFormat conflict

All linting checks now pass with zero errors and warnings.

macOS/InstancesSettings.swift

@@ -71,11 +71,7 @@ struct InstancesSettings: View {
                     }
                 }
 
-                if #available(macOS 12.0, *) {
-                    list.listStyle(.inset(alternatesRowBackgrounds: true))
-                } else {
-                    list.listStyle(.inset)
-                }
+                list.listStyle(.inset(alternatesRowBackgrounds: true))
             }
 
             if selectedInstance != nil, selectedInstance.app.hasFrontendURL {