feat(workspace): image blocks via /bild (M2)

- /bild (only in an empty bullet) turns the bullet into an inline picker:
  file, camera on phones, drag & drop, paste, or an https link the server
  copies. Esc/✕ restores the empty bullet; nothing is synced before the
  upload succeeded.
- Photos are shrunk to 2048 px and stored as WebP (JPEG fallback); the
  re-encoding drops EXIF data such as the location.
- Image block: loaded with the login as blob URL, click opens full
  screen, optional caption kept in the block content
  (![caption](media:id)).

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

frontend/src/features/workspace/OutlinerBlock.tsx

@@ -20,10 +20,14 @@ import {
   FileText,
   Lock,
   AlertTriangle,
+  Image as ImageIcon,
 } from 'lucide-react';
 import { DocumentBlock, BlockType } from '../../lib/types';
 import { LinkModal } from './LinkModal';
 import { CodeBlockEditor, resolveLanguageId, isUnambiguousLanguageShortcut } from './CodeBlockEditor';
+import { ImagePicker } from './ImagePicker';
+import { ImageBlock } from './ImageBlock';
+import { mediaContent, parseMediaContent } from '../../lib/media';
 import { renderInlineMarkdown } from '../../lib/markdown';
 import { api } from '../../lib/api';
 import { safeHref } from '../../lib/safeUrl';
@@ -33,6 +37,8 @@ export interface SlashCommand {
   label: string;
   desc: string;
   icon: React.ReactNode;
+  /** Only offered in an empty bullet; the bullet turns into an inline picker first */
+  media?: boolean;
 }
 
 const SLASH_COMMANDS: SlashCommand[] = [
@@ -44,6 +50,7 @@ const SLASH_COMMANDS: SlashCommand[] = [
   { type: 'code', label: '/code', desc: 'Code-Block mit Syntax', icon: <Code className="w-3.5 h-3.5" /> },
   { type: 'callout', label: '/callout', desc: 'Hinweisbox', icon: <MessageSquare className="w-3.5 h-3.5" /> },
   { type: 'divider', label: '/divider', desc: 'Trennlinie', icon: <Minus className="w-3.5 h-3.5" /> },
+  { type: 'image', label: '/bild', desc: 'Bild hochladen, fotografieren oder verlinken (image)', icon: <ImageIcon className="w-3.5 h-3.5" />, media: true },
 ];
 
 export interface OutlinerBlockProps {
@@ -134,6 +141,8 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
   // A block someone else is editing can still get the cursor (read-only), e.g. to press Enter at its end
   const canFocus = canEdit || (!!lockedBy && !!canAppendBelow);
   const [slashSearch, setSlashSearch] = useState<string | null>(null);
+  // Inline picker an empty bullet turns into after /bild (local only, nothing synced until done)
+  const [mediaPicker, setMediaPicker] = useState<'image' | null>(null);
   const [slashIndex, setSlashIndex] = useState(0);
   const [showLinkModal, setShowLinkModal] = useState<boolean>(false);
   const [showTodoMenu, setShowTodoMenu] = useState<boolean>(false);
@@ -329,10 +338,14 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
     if (slashSearch === null) return [];
     const q = slashSearch.toLowerCase();
     const cmdQuery = q.startsWith('code ') ? 'code' : q;
+    // Media only in an otherwise empty bullet
+    const emptyBullet = localContent.replace(/\/(code\s+[a-z0-9_+#.-]*|[a-z0-9]*)$/i, '').trim() === '';
     return SLASH_COMMANDS.filter(
-      (c) => c.label.toLowerCase().includes(cmdQuery) || c.desc.toLowerCase().includes(cmdQuery)
+      (c) =>
+        (!c.media || emptyBullet) &&
+        (c.label.toLowerCase().includes(cmdQuery) || c.desc.toLowerCase().includes(cmdQuery))
     );
-  }, [slashSearch]);
+  }, [slashSearch, localContent]);
 
   const applySlashCommand = (cmd: SlashCommand) => {
     setSlashSearch(null);
@@ -343,6 +356,14 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
       setShowLinkModal(true);
       return;
     }
+    if (cmd.media) {
+      // The typed "/bild" must not stay in the synced text; the block type changes only after the upload
+      setLocalContent('');
+      localContentRef.current = '';
+      flushDebounce('');
+      setMediaPicker(cmd.type as 'image');
+      return;
+    }
     const langOverride =
       cmd.type === 'code' && codeLangMatch
         ? resolveLanguageId(codeLangMatch[1]) || codeLangMatch[1].toLowerCase()
@@ -814,7 +835,35 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
 
       {/* Main Block Content */}
       <div className="flex-1 min-w-0 pr-1 relative min-h-[1.5rem]">
-        {block.type === 'divider' ? (
+        {mediaPicker === 'image' ? (
+          <ImagePicker
+            docId={docId}
+            onDone={(media) => {
+              setMediaPicker(null);
+              const content = mediaContent('image', media.id);
+              setLocalContent(content);
+              localContentRef.current = content;
+              flushDebounce(content, { type: 'image' });
+            }}
+            onCancel={() => {
+              setMediaPicker(null);
+              requestAnimationFrame(() => textareaRef.current?.focus());
+            }}
+          />
+        ) : block.type === 'image' ? (
+          <ImageBlock
+            content={localContent}
+            canEdit={canEdit}
+            onCaptionChange={(caption) => {
+              const ref = parseMediaContent(localContent);
+              if (!ref) return;
+              const content = mediaContent('image', ref.id, caption);
+              setLocalContent(content);
+              localContentRef.current = content;
+              flushDebounce(content);
+            }}
+          />
+        ) : block.type === 'divider' ? (
           <div className="py-2">
             <hr className="border-t border-border" />
           </div>