fix: resolve all 12 TypeScript errors (tsc --noEmit clean)

- mail.ts: add explicit types to decodeMimeHeader callback params
- SessionList.tsx: use React.MouseEvent instead of nativeEvent
- ComposeModal.tsx: construct name from first_name + last_name
- MailDetail.tsx: destructure onReply/onForward from props
- RichTextEditor.tsx: use SetContentOptions object instead of boolean
- MailSearchBar.tsx: add optional value prop to interface
- EmptyState.tsx: add optional children prop
- Badge.tsx: add secondary variant to BadgeVariant, variantClasses, dotColors
- ConfirmDialog.tsx: add optional children prop
- hooks.ts: extend SearchResult type to include mail/file/event

frontend/src/components/mail/RichTextEditor.tsx

@@ -88,7 +88,7 @@ export function RichTextEditor({ content, onChange, placeholder, editable = true
   // Sync external content changes (e.g. template/signature insert, reply/forward/draft load)
   React.useEffect(() => {
     if (editor && content !== editor.getHTML()) {
-      editor.commands.setContent(content, false);
+      editor.commands.setContent(content, { emitUpdate: false });
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [content, editor]);