feat: emoji picker in create dialogs; due date and priority right under a deepened task; no flicker on kanban drop

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

frontend/src/components/EmojiIconButton.tsx

@@ -0,0 +1,41 @@
+import React, { useRef, useState } from 'react';
+import { EmojiPickerModal } from '../features/workspace/EmojiPickerModal';
+
+interface EmojiIconButtonProps {
+  value: string;
+  onChange: (emoji: string) => void;
+  // Default icon; removing the icon in the picker goes back to it
+  fallback: string;
+}
+
+// Icon field of the create dialogs (note, task list, list): the emoji as a button that opens the same
+// picker as the icon of an open note (Doku/ui-patterns.md).
+export const EmojiIconButton: React.FC<EmojiIconButtonProps> = ({ value, onChange, fallback }) => {
+  const buttonRef = useRef<HTMLButtonElement>(null);
+  const [anchor, setAnchor] = useState<DOMRect | null>(null);
+  return (
+    <>
+      <button
+        ref={buttonRef}
+        type="button"
+        onClick={() => setAnchor((cur) => (cur ? null : buttonRef.current?.getBoundingClientRect() ?? null))}
+        title="Icon auswählen"
+        aria-label="Icon auswählen"
+        className="w-12 sm:w-10 h-11 sm:h-8 flex-shrink-0 flex items-center justify-center input-field text-lg sm:text-base leading-none cursor-pointer hover:border-strong"
+      >
+        {value || fallback}
+      </button>
+      {anchor && (
+        <EmojiPickerModal
+          currentIcon={value}
+          anchor={anchor}
+          onSelectEmoji={(emoji) => {
+            onChange(emoji || fallback);
+            setAnchor(null);
+          }}
+          onClose={() => setAnchor(null)}
+        />
+      )}
+    </>
+  );
+};