feat: knowledge graph table view met sort, group en bulk edit

Voegt een Graph/Table toggle toe aan de admin Knowledge Graph. De tabel
ondersteunt sorteren per kolom, groeperen op type/relevance/theme/difficulty,
filteren op label, multi-select en bulk-wijzigen van type, learning_relevance
en relevance_locked.

Closes #10

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/hooks/useGraphData.js

@@ -104,6 +104,23 @@ export function useGraphData() {
     return true;
   }, []);
 
+  /**
+   * Apply the same patch to many topics in one call. `ids` is the set of
+   * topic IDs to update; `patch` is the partial-topic to merge into each one
+   * (e.g. `{ type: 'process' }` or `{ learning_relevance: 'core', relevance_locked: true }`).
+   *
+   * Persists each topic via db.upsertTopic in parallel and mirrors into state.
+   * Returns the number of topics actually written (selected ∩ existing).
+   */
+  const bulkUpdateTopics = useCallback(async (ids, patch) => {
+    const idSet = new Set(ids);
+    const targets = topicsRef.current.filter(t => idSet.has(t.id));
+    const updated = targets.map(t => ({ ...t, ...patch }));
+    await Promise.all(updated.map(t => db.upsertTopic(t)));
+    setTopics(prev => prev.map(t => (idSet.has(t.id) ? { ...t, ...patch } : t)));
+    return updated.length;
+  }, []);
+
   /** Remove a specific (source, target, type) relation triple. */
   const removeRelation = useCallback(async (source, target, type) => {
     await db.removeRelation(source, target, type);
@@ -165,6 +182,7 @@ export function useGraphData() {
     snapshotMeta,
     reload,
     updateTopic,
+    bulkUpdateTopics,
     deleteTopic,
     addRelation,
     removeRelation,