refactor: migrate all icons from Untitled UI to FontAwesome Pro Duotone

Replace all @untitledui/icons imports across 55 files with equivalent
@fortawesome/pro-duotone-svg-icons icons, using FontAwesomeIcon wrappers
(FC<{ className?: string }>) for prop-based usage and inline replacements
for direct JSX usage. Drops unsupported Untitled UI-specific props
(strokeWidth, numeric size). TypeScript compiles clean with no errors.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/base/buttons/close-button.tsx

@@ -1,4 +1,5 @@
-import { X as CloseIcon } from "@untitledui/icons";
+import { FontAwesomeIcon } from "@fortawesome/react-fontawesome";
+import { faXmark } from "@fortawesome/pro-duotone-svg-icons";
 import { Button as AriaButton, type ButtonProps as AriaButtonProps } from "react-aria-components";
 import { cx } from "@/utils/cx";
 
@@ -34,7 +35,7 @@ export const CloseButton = ({ label, className, size = "sm", theme = "light", ..
                 )
             }
         >
-            <CloseIcon aria-hidden="true" className={cx("shrink-0 transition-inherit-all", sizes[size].icon)} />
+            <FontAwesomeIcon icon={faXmark} aria-hidden="true" className={cx("shrink-0 transition-inherit-all", sizes[size].icon)} />
         </AriaButton>
     );
 };