test(tag): add subtreeDocumentCount to admin tree fixtures (#698)

TagTreeNodeDTO now requires subtreeDocumentCount, so the admin sidebar test
fixtures (TagTreeNode, TagsListPanel) need the field to type-check. The admin
sidebar still renders the direct documentCount — these fixtures only gain the
new field, no behaviour change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/routes/admin/tags/TagTreeNode.svelte.test.ts

@@ -22,6 +22,7 @@ const leafNode = (overrides: Record<string, unknown> = {}) => ({
 	name: 'Personen',
 	color: 'sage',
 	documentCount: 5,
+	subtreeDocumentCount: 5,
 	parentId: null,
 	children: [],
 	...overrides
@@ -32,8 +33,18 @@ const parentNode = (overrides: Record<string, unknown> = {}) => ({
 	name: 'Orte',
 	color: 'sienna',
 	documentCount: 0,
+	subtreeDocumentCount: 2,
 	parentId: null,
-	children: [{ id: 'tc1', name: 'Berlin', color: null, documentCount: 2, children: [] }],
+	children: [
+		{
+			id: 'tc1',
+			name: 'Berlin',
+			color: null,
+			documentCount: 2,
+			subtreeDocumentCount: 2,
+			children: []
+		}
+	],
 	...overrides
 });
 

frontend/src/routes/admin/tags/layout.svelte.spec.ts

@@ -15,9 +15,18 @@ const tree = [
 		name: 'Familie',
 		color: undefined,
 		documentCount: 3,
+		subtreeDocumentCount: 5,
 		parentId: undefined,
 		children: [
-			{ id: 't2', name: 'Eltern', color: undefined, documentCount: 2, parentId: 't1', children: [] }
+			{
+				id: 't2',
+				name: 'Eltern',
+				color: undefined,
+				documentCount: 2,
+				subtreeDocumentCount: 2,
+				parentId: 't1',
+				children: []
+			}
 		]
 	},
 	{
@@ -25,6 +34,7 @@ const tree = [
 		name: 'Urlaub',
 		color: 'teal',
 		documentCount: 0,
+		subtreeDocumentCount: 0,
 		parentId: undefined,
 		children: []
 	}
@@ -128,6 +138,7 @@ describe('TagsListPanel — color dot', () => {
 					id: 't1',
 					name: 'Familie',
 					documentCount: 0,
+					subtreeDocumentCount: 0,
 					parentId: undefined,
 					children: [],
 					color: undefined