refactor: unify focus styles across all input fields

Replace inconsistent focus border styles with a unified soft blue ring effect
across all input and textarea components.

Changes:
- Add consistent focus:ring styles to Input and Textarea components
- Use focus:ring-blue-500/20 (light) and focus:ring-blue-400/20 (dark)
- Remove focus border color changes for a more subtle design
- Update ApiKeyInput to match the unified focus style
- Update all manual textarea elements (Codex and Claude configs)

Benefits:
- Consistent visual feedback across all form inputs
- Soft, elegant focus indication with blue glow effect
- No jarring border color changes
- Better user experience with subtle, professional styling

The focus effect now uses only a soft blue ring (20% opacity) without
changing border colors, creating a more refined and less distracting
interaction pattern.

src/components/providers/forms/ApiKeyInput.tsx

@@ -30,8 +30,8 @@ const ApiKeyInput: React.FC<ApiKeyInputProps> = ({
 
   const inputClass = `w-full px-3 py-2 pr-10 border rounded-lg text-sm transition-colors ${
     disabled
-      ? "bg-gray-100 dark:bg-gray-800 border-border-default  text-gray-400 dark:text-gray-500 cursor-not-allowed"
-      : "border-border-default  dark:bg-gray-800 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-blue-500/20 dark:focus:ring-blue-400/20 focus:border-border-active "
+      ? "bg-gray-100 dark:bg-gray-800 border-border-default text-gray-400 dark:text-gray-500 cursor-not-allowed"
+      : "border-border-default dark:bg-gray-800 dark:text-gray-100 focus:outline-none focus:ring-2 focus:ring-blue-500/20 dark:focus:ring-blue-400/20"
   }`;
 
   return (