feat(UI-Overhaul-Phase3): Wiki WYSIWYG Editor mit Tiptap

- WikiEditor.tsx: Complete rebuild with Tiptap WYSIWYG editor
  - Notion-style floating toolbar with bold/italic/underline/strike
  - Headings (H1/H2/H3), bullet/ordered lists, blockquote, code blocks
  - Link and image insertion
  - Text alignment (left/center/right)
  - Undo/redo support
  - HTML-to-Markdown conversion for backend storage
  - Markdown-to-HTML conversion for editor initialization
- Wiki.tsx: View/Edit mode toggle
  - View mode: Rendered Markdown (ReactMarkdown)
  - Edit mode: WYSIWYG editor (Tiptap)
  - Inline save button in edit mode
  - wikiMode resets to view when selecting new article
  - handleInlineSave saves article content directly

tsc clean

frontend/src/components/wiki/WikiEditor.tsx

@@ -1,16 +1,27 @@
 /**
- * WikiEditor — Markdown editor with live preview.
+ * WikiEditor — WYSIWYG editor using Tiptap (Notion-style).
  *
- * Uses a textarea for Markdown input and react-markdown + remark-gfm for
- * the live preview pane. Content is stored as Markdown in the backend.
+ * Features: Floating toolbar, Markdown export for backend storage,
+ * bold/italic/underline/strike, headings, lists, links, code blocks, images.
  */
 
-import React, { useMemo, useState } from 'react';
+import React, { useEffect, useCallback } from 'react';
 import { useTranslation } from 'react-i18next';
-import ReactMarkdown from 'react-markdown';
-import remarkGfm from 'remark-gfm';
+import { useEditor, EditorContent, Editor } from '@tiptap/react';
+import StarterKit from '@tiptap/starter-kit';
+import Underline from '@tiptap/extension-underline';
+import Link from '@tiptap/extension-link';
+import Image from '@tiptap/extension-image';
+import Placeholder from '@tiptap/extension-placeholder';
+import TextAlign from '@tiptap/extension-text-align';
+import { TextStyle } from "@tiptap/extension-text-style";
+import Color from '@tiptap/extension-color';
 import clsx from 'clsx';
-import { Eye, PencilLine, Columns2 } from 'lucide-react';
+import {
+  Bold, Italic, Underline as UnderlineIcon, Strikethrough, Heading1, Heading2, Heading3,
+  List, ListOrdered, Quote, Code, Link as LinkIcon, Image as ImageIcon,
+  AlignLeft, AlignCenter, AlignRight, Undo, Redo,
+} from 'lucide-react';
 
 export interface WikiEditorProps {
   value: string;
@@ -19,61 +30,187 @@ export interface WikiEditorProps {
   minHeight?: string;
 }
 
-type EditorMode = 'write' | 'preview' | 'split';
-
-export function WikiEditor({ value, onChange, placeholder, minHeight = 'min-h-72' }: WikiEditorProps) {
-  const { t } = useTranslation();
-  const [mode, setMode] = useState<EditorMode>('split');
-
-  const preview = useMemo(
-    () => (
-      <div className="prose prose-sm max-w-none px-4 py-3 text-secondary-800">
-        <ReactMarkdown remarkPlugins={[remarkGfm]}>{value || t('wiki.editor.emptyPreview')}</ReactMarkdown>
-      </div>
-    ),
-    [value, t]
-  );
-
-  const modeButton = (m: EditorMode, label: string, Icon: React.ComponentType<{ className?: string }>) => (
+function ToolbarButton({
+  onClick, isActive, disabled, icon: Icon, label,
+}: {
+  onClick: () => void;
+  isActive?: boolean;
+  disabled?: boolean;
+  icon: React.ComponentType<{ className?: string }>;
+  label: string;
+}) {
+  return (
     <button
       type="button"
-      onClick={() => setMode(m)}
+      onClick={onClick}
+      disabled={disabled}
       className={clsx(
-        'inline-flex items-center gap-1.5 px-3 py-1.5 rounded-md text-sm font-medium min-h-touch transition-colors',
-        mode === m ? 'bg-primary-600 text-white' : 'text-secondary-600 hover:bg-secondary-100'
+        'p-1.5 rounded-md transition-colors min-h-touch min-w-touch',
+        isActive ? 'bg-primary-100 text-primary-700' : 'text-secondary-600 hover:bg-secondary-100',
+        disabled && 'opacity-40 cursor-not-allowed',
       )}
-      aria-pressed={mode === m}
+      aria-label={label}
+      title={label}
     >
-      <Icon className="h-4 w-4" aria-hidden="true" />
-      {label}
+      <Icon className="h-4 w-4" />
     </button>
   );
+}
+
+function Toolbar({ editor }: { editor: Editor | null }) {
+  const { t } = useTranslation();
+  if (!editor) return null;
+
+  const setLink = useCallback(() => {
+    const previousUrl = editor.getAttributes('link').href;
+    const url = window.prompt('URL', previousUrl);
+    if (url === null) return;
+    if (url === '') {
+      editor.chain().focus().extendMarkRange('link').unsetLink().run();
+      return;
+    }
+    editor.chain().focus().extendMarkRange('link').setLink({ href: url }).run();
+  }, [editor]);
+
+  const addImage = useCallback(() => {
+    const url = window.prompt('Bild URL');
+    if (url) editor.chain().focus().setImage({ src: url }).run();
+  }, [editor]);
 
   return (
-    <div className="border border-secondary-300 rounded-md overflow-hidden">
-      <div className="flex items-center gap-1 border-b border-secondary-200 bg-secondary-50 px-2 py-1.5">
-        {modeButton('write', t('editor.write'), PencilLine)}
-        {modeButton('preview', t('editor.preview'), Eye)}
-        {modeButton('split', t('editor.split'), Columns2)}
-      </div>
-      <div className={clsx('grid', mode === 'split' ? 'grid-cols-1 md:grid-cols-2' : 'grid-cols-1')}>
-        {(mode === 'write' || mode === 'split') && (
-          <textarea
-            value={value}
-            onChange={(e) => onChange(e.target.value)}
-            placeholder={placeholder}
-            aria-label={t('editor.writeLabel')}
-            className={clsx(
-              'w-full resize-y border-0 focus:outline-none focus:ring-0 p-4 text-sm font-mono text-secondary-900 bg-white',
-              mode === 'split' && 'border-b md:border-b-0 md:border-r border-secondary-200',
-              minHeight
-            )}
-          />
-        )}
-        {(mode === 'preview' || mode === 'split') && (
-          <div className={clsx('bg-secondary-50 border-0 overflow-y-auto', minHeight)}>{preview}</div>
-        )}
-      </div>
+    <div className="flex items-center gap-0.5 flex-wrap border-b border-secondary-200 bg-secondary-50 px-2 py-1.5 sticky top-0 z-10">
+      <ToolbarButton onClick={() => editor.chain().focus().undo().run()} disabled={!editor.can().undo()} icon={Undo} label={t('common.undo', 'Rückgängig')} />
+      <ToolbarButton onClick={() => editor.chain().focus().redo().run()} disabled={!editor.can().redo()} icon={Redo} label={t('common.redo', 'Wiederholen')} />
+      <div className="w-px h-5 bg-secondary-200 mx-1" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleBold().run()} isActive={editor.isActive('bold')} icon={Bold} label="Bold" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleItalic().run()} isActive={editor.isActive('italic')} icon={Italic} label="Italic" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleUnderline().run()} isActive={editor.isActive('underline')} icon={UnderlineIcon} label="Underline" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleStrike().run()} isActive={editor.isActive('strike')} icon={Strikethrough} label="Strike" />
+      <div className="w-px h-5 bg-secondary-200 mx-1" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleHeading({ level: 1 }).run()} isActive={editor.isActive('heading', { level: 1 })} icon={Heading1} label="H1" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleHeading({ level: 2 }).run()} isActive={editor.isActive('heading', { level: 2 })} icon={Heading2} label="H2" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleHeading({ level: 3 }).run()} isActive={editor.isActive('heading', { level: 3 })} icon={Heading3} label="H3" />
+      <div className="w-px h-5 bg-secondary-200 mx-1" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleBulletList().run()} isActive={editor.isActive('bulletList')} icon={List} label="Bullet List" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleOrderedList().run()} isActive={editor.isActive('orderedList')} icon={ListOrdered} label="Ordered List" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleBlockquote().run()} isActive={editor.isActive('blockquote')} icon={Quote} label="Quote" />
+      <ToolbarButton onClick={() => editor.chain().focus().toggleCodeBlock().run()} isActive={editor.isActive('codeBlock')} icon={Code} label="Code Block" />
+      <div className="w-px h-5 bg-secondary-200 mx-1" />
+      <ToolbarButton onClick={setLink} isActive={editor.isActive('link')} icon={LinkIcon} label="Link" />
+      <ToolbarButton onClick={addImage} icon={ImageIcon} label="Image" />
+      <div className="w-px h-5 bg-secondary-200 mx-1" />
+      <ToolbarButton onClick={() => editor.chain().focus().setTextAlign('left').run()} isActive={editor.isActive({ textAlign: 'left' })} icon={AlignLeft} label="Left" />
+      <ToolbarButton onClick={() => editor.chain().focus().setTextAlign('center').run()} isActive={editor.isActive({ textAlign: 'center' })} icon={AlignCenter} label="Center" />
+      <ToolbarButton onClick={() => editor.chain().focus().setTextAlign('right').run()} isActive={editor.isActive({ textAlign: 'right' })} icon={AlignRight} label="Right" />
+    </div>
+  );
+}
+
+// Convert HTML to simple Markdown for backend storage
+function htmlToMarkdown(html: string): string {
+  const tempDiv = document.createElement('div');
+  tempDiv.innerHTML = html;
+
+  function convertNode(node: Node): string {
+    if (node.nodeType === Node.TEXT_NODE) return node.textContent || '';
+    if (node.nodeType !== Node.ELEMENT_NODE) return '';
+    const el = node as HTMLElement;
+    const tag = el.tagName.toLowerCase();
+    const content = Array.from(el.childNodes).map(convertNode).join('');
+
+    switch (tag) {
+      case 'h1': return `\n# ${content}\n\n`;
+      case 'h2': return `\n## ${content}\n\n`;
+      case 'h3': return `\n### ${content}\n\n`;
+      case 'strong': case 'b': return `**${content}**`;
+      case 'em': case 'i': return `*${content}*`;
+      case 'u': return content;
+      case 's': case 'del': return `~~${content}~~`;
+      case 'ul': return Array.from(el.children).map(li => `- ${convertNode(li).trim()}`).join('\n') + '\n\n';
+      case 'ol': return Array.from(el.children).map((li, i) => `${i + 1}. ${convertNode(li).trim()}`).join('\n') + '\n\n';
+      case 'li': return content;
+      case 'blockquote': return `> ${content.trim()}\n\n`;
+      case 'pre': return `\n\`\`\`\n${el.textContent}\n\`\`\`\n\n`;
+      case 'code': return `\`${content}\``;
+      case 'a': return `[${content}](${el.getAttribute('href') || ''})`;
+      case 'img': return `![${el.getAttribute('alt') || ''}](${el.getAttribute('src') || ''})`;
+      case 'br': return '\n';
+      case 'p': return `${content}\n\n`;
+      default: return content;
+    }
+  }
+
+  return convertNode(tempDiv).trim();
+}
+
+// Convert simple Markdown to HTML for editor initialization
+function markdownToHtml(md: string): string {
+  if (!md) return '';
+  // Basic markdown to HTML conversion
+  let html = md
+    .replace(/^### (.+)$/gm, '<h3>$1</h3>')
+    .replace(/^## (.+)$/gm, '<h2>$1</h2>')
+    .replace(/^# (.+)$/gm, '<h1>$1</h1>')
+    .replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>')
+    .replace(/\*(.+?)\*/g, '<em>$1</em>')
+    .replace(/~~(.+?)~~/g, '<s>$1</s>')
+    .replace(/`(.+?)`/g, '<code>$1</code>')
+    .replace(/^> (.+)$/gm, '<blockquote>$1</blockquote>')
+    .replace(/\[([^\]]+)\]\(([^)]+)\)/g, '<a href="$2">$1</a>')
+    .replace(/!\[([^\]]*)\]\(([^)]+)\)/g, '<img src="$2" alt="$1" />')
+    .replace(/^\- (.+)$/gm, '<li>$1</li>')
+    .replace(/^\d+\. (.+)$/gm, '<li>$1</li>');
+  // Wrap loose text in paragraphs
+  html = html.split(/\n\n+/).map(block => {
+    if (block.match(/^<(h[1-3]|ul|ol|blockquote|pre)/)) return block;
+    if (block.trim()) return `<p>${block.replace(/\n/g, '<br />')}</p>`;
+    return '';
+  }).join('\n');
+  return html;
+}
+
+export function WikiEditor({ value, onChange, placeholder, minHeight = 'min-h-72' }: WikiEditorProps) {
+  const editor = useEditor({
+    extensions: [
+      StarterKit,
+      Underline,
+      Link.configure({ openOnClick: false }),
+      Image,
+      Placeholder.configure({ placeholder: placeholder || 'Schreibe hier...' }),
+      TextAlign.configure({ types: ['heading', 'paragraph'] }),
+      TextStyle,
+      Color,
+    ],
+    content: markdownToHtml(value),
+    onUpdate: ({ editor }) => {
+      const html = editor.getHTML();
+      const md = htmlToMarkdown(html);
+      onChange(md);
+    },
+    editorProps: {
+      attributes: {
+        class: clsx(
+          'prose prose-sm max-w-none p-4 focus:outline-none',
+          'min-h-72 text-secondary-900',
+        ),
+      },
+    },
+  });
+
+  // Update content when value changes externally
+  useEffect(() => {
+    if (editor && value !== undefined) {
+      const currentMd = htmlToMarkdown(editor.getHTML());
+      if (currentMd !== value) {
+        editor.commands.setContent(markdownToHtml(value), { emitUpdate: false });
+      }
+    }
+  }, [value, editor]);
+
+  return (
+    <div className="border border-secondary-300 rounded-md overflow-hidden">
+      <Toolbar editor={editor} />
+      <EditorContent editor={editor} className={clsx('bg-white overflow-y-auto', minHeight)} />
     </div>
   );
 }

frontend/src/pages/Wiki.tsx

@@ -81,6 +81,7 @@ export function WikiPage() {
   const [deleting, setDeleting] = useState(false);
   const [restoring, setRestoring] = useState(false);
   const [browserRefreshKey, setBrowserRefreshKey] = useState(0);
+  const [wikiMode, setWikiMode] = useState<'view' | 'edit'>('view');
 
   const loadCategories = useCallback(async () => {
     try {
@@ -112,6 +113,7 @@ export function WikiPage() {
   const handleSelectArticle = useCallback(
     (a: WikiArticle) => {
       void loadArticle(a.id);
+      setWikiMode('view');
     },
     [loadArticle]
   );
@@ -172,6 +174,30 @@ export function WikiPage() {
     }
   }, [form, editingId, t, toast]);
 
+  // Inline save from View/Edit mode toggle
+  const handleInlineSave = useCallback(async () => {
+    if (!article) return;
+    setSaving(true);
+    try {
+      const updated = await updateWikiArticle(article.id, {
+        title: article.title,
+        content: article.content,
+        summary: article.summary,
+        category_id: article.category_id,
+        tags: article.tags,
+        status: article.status,
+      });
+      setArticle(updated);
+      toast.success(t('knowledge.editor.updated'));
+      setWikiMode('view');
+      setBrowserRefreshKey((k) => k + 1);
+    } catch (err) {
+      toast.error(err instanceof Error ? err.message : t('knowledge.editor.saveError'));
+    } finally {
+      setSaving(false);
+    }
+  }, [article, t, toast]);
+
   const handleDelete = useCallback(async () => {
     if (!deleteTarget) return;
     setDeleting(true);
@@ -255,12 +281,22 @@ export function WikiPage() {
               actions={
                 <div className="flex items-center gap-2">
                   {statusBadge}
+                  <Button
+                    variant="ghost"
+                    size="sm"
+                    onClick={() => setWikiMode(wikiMode === 'view' ? 'edit' : 'view')}
+                    icon={wikiMode === 'view' ? <Pencil className="h-4 w-4" aria-hidden="true" /> : <History className="h-4 w-4" aria-hidden="true" />}
+                  >
+                    {wikiMode === 'view' ? t('common.edit') : t('common.preview', 'Vorschau')}
+                  </Button>
+                  {wikiMode === 'edit' && (
+                    <Button variant="ghost" size="sm" onClick={() => void handleInlineSave()} isLoading={saving}>
+                      {t('common.save')}
+                    </Button>
+                  )}
                   <Button variant="ghost" size="sm" onClick={() => void loadVersions()} icon={<History className="h-4 w-4" aria-hidden="true" />}>
                     {t('knowledge.versions.title')}
                   </Button>
-                  <Button variant="ghost" size="sm" onClick={openEdit} icon={<Pencil className="h-4 w-4" aria-hidden="true" />}>
-                    {t('common.edit')}
-                  </Button>
                   <Button variant="danger" size="sm" onClick={() => setDeleteTarget(article)} icon={<Trash2 className="h-4 w-4" aria-hidden="true" />}>
                     {t('common.delete')}
                   </Button>
@@ -308,9 +344,19 @@ export function WikiPage() {
                 </div>
               )}
 
-              <div className="prose prose-sm max-w-none">
-                <ReactMarkdown remarkPlugins={[remarkGfm]}>{article.content || t('wiki.detail.emptyContent')}</ReactMarkdown>
-              </div>
+              {wikiMode === 'edit' ? (
+                <div>
+                  <WikiEditor
+                    value={article.content}
+                    onChange={(value) => setArticle({ ...article, content: value })}
+                    placeholder={t('wiki.editor.contentPlaceholder')}
+                  />
+                </div>
+              ) : (
+                <div className="prose prose-sm max-w-none">
+                  <ReactMarkdown remarkPlugins={[remarkGfm]}>{article.content || t('wiki.detail.emptyContent')}</ReactMarkdown>
+                </div>
+              )}
             </Card>
           ) : (
             <EmptyState