feat(palace): extract KG triples from entities + refresh L1 cache on note save

After storing memories, generate subject-predicate-object triples from
entity pairs found in extracted memories. Also trigger L1 critical facts
cache regeneration so wake-up context stays fresh.

backend/src/modules/palace/palace-hooks.ts

@@ -9,8 +9,9 @@
 import { config } from '../../lib/config.js';
 import { embedText, stripHtmlForEmbedding } from '../../lib/embeddings.js';
 import { trackEvent } from '../../lib/telemetry.js';
-import { ensureWing, ensureRoom, storeMemory, isNearDuplicate } from './repository.js';
+import { ensureWing, ensureRoom, storeMemory, isNearDuplicate, addTriple } from './repository.js';
 import { extractMemories } from './extractor.js';
+import { regenerateCriticalFacts } from './wakeup.js';
 import type { NoteDoc } from '../notes/types.js';
 import type { FastifyBaseLogger } from 'fastify';
 
@@ -61,13 +62,32 @@ export async function onNoteSavedToPalace(
     }
 
     if (stored > 0) {
+      // Extract KG triples from entities found in memories
+      let triplesStored = 0;
+      for (const mem of memories) {
+        if (mem.entities.length >= 2) {
+          for (let i = 0; i < mem.entities.length - 1; i++) {
+            await addTriple(
+              userId, productId, wing.id,
+              mem.entities[i], `related_via_${mem.hall}`, mem.entities[i + 1],
+              0.7, note.id,
+            ).catch(() => {});
+            triplesStored++;
+          }
+        }
+      }
+
+      // Refresh L1 critical facts cache
+      void regenerateCriticalFacts(userId, productId, wing.id).catch(() => {});
+
       trackEvent('palace.memories_extracted', userId, {
         noteId: note.id,
         wingId: wing.id,
         stored: String(stored),
         skippedDup: String(skippedDup),
+        triples: String(triplesStored),
       });
-      log.info({ noteId: note.id, stored, skippedDup }, 'palace: memories extracted from note');
+      log.info({ noteId: note.id, stored, skippedDup, triplesStored }, 'palace: memories + triples extracted from note');
     }
   } catch (err) {
     log.warn({ noteId: note.id, err }, 'palace: memory extraction failed');