T08a: Frontend DMS + Tags + Permissions UI — 33 tests, tsc clean, vite build pass

- DMS file browser: folder tree + file grid + upload dropzone + search + preview modal
- DMS share dialog: user/group share + public share links with password+expiry
- DMS bulk actions: bulk move + bulk delete with confirm dialogs
- DMS trash view: deleted files list with restore button
- Tags: TagPicker on company/contact detail pages (new tabs tab)
- Tags: TagCloud + BulkTagDialog for bulk tag assignment
- Permissions: share link creation, permission display, copy-link button
- API clients: dms.ts, tags.ts, permissions.ts
- Routes: /dms, /dms/trash added to router
- Sidebar: DMS nav link updated
- i18n: de.json + en.json translations for DMS/Tags/Permissions
- 33 new tests (5 test files), full regression 276/276 pass
- tsc --noEmit: 0 errors, vite build: 252 modules

frontend/src/pages/CompanyDetail.tsx

@@ -9,6 +9,7 @@ import { Badge } from '@/components/ui/Badge';
 import { EmptyState } from '@/components/ui/EmptyState';
 import { Skeleton } from '@/components/ui/Skeleton';
 import { Avatar } from '@/components/ui/Avatar';
+import { TagPicker } from '@/components/tags/TagPicker';
 
 export function CompanyDetailPage() {
   const { id } = useParams<{ id: string }>();
@@ -103,6 +104,14 @@ export function CompanyDetailPage() {
     ),
   };
 
+  const tagsTab: TabItem = {
+    key: 'tags',
+    label: t('tags.title'),
+    content: (
+      <TagPicker entityType="company" entityId={company.id} />
+    ),
+  };
+
   const filesTab: TabItem = {
     key: 'files',
     label: t('companies.files'),
@@ -128,7 +137,7 @@ export function CompanyDetailPage() {
           {t('common.edit')}
         </Button>
       </div>
-      <Tabs tabs={[overviewTab, contactsTab, filesTab, activityTab]} defaultKey="overview" />
+      <Tabs tabs={[overviewTab, contactsTab, tagsTab, filesTab, activityTab]} defaultKey="overview" />
     </div>
   );
 }