feat: select text across bullets and delete it like a text editor; Ctrl+Z in tasks; notes and lists without emoji; custom done columns complete tasks

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/workspace/LinkModal.tsx

@@ -362,7 +362,7 @@ export const LinkModal: React.FC<LinkModalProps> = ({
                     className="flex items-center justify-between p-2.5 bg-canvas border border-border rounded-card hover:border-accent/60 transition-colors group cursor-pointer"
                   >
                     <div className="flex items-center gap-2.5 min-w-0">
-                      <span className="text-base shrink-0">{d.icon || '🗒️'}</span>
+                      {d.icon && <span className="text-base shrink-0">{d.icon}</span>}
                       <div className="min-w-0">
                         <div className="text-xs font-semibold text-main truncate group-hover:text-accent">
                           {d.title || 'Unbenannte Notiz'}