fix: align IDs with metadatas in ChromaSearchStrategy

ChromaSync.queryChroma() returns deduplicated sqlite_ids but the
metadatas array contains multiple entries per observation (narrative +
facts). The filterByRecency() method was iterating over metadatas and
using the index to access ids, causing array out-of-bounds access.

The fix builds a Map from sqlite_id to metadata, then iterates over
the deduplicated ids array to ensure proper alignment.

Symptoms before fix:
- Semantic search returning incorrect/empty results
- Search only working with near-exact queries
- Recent items (same day) not being found

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/services/worker/search/strategies/ChromaSearchStrategy.ts

@@ -167,6 +167,13 @@ export class ChromaSearchStrategy extends BaseSearchStrategy implements SearchSt
 
   /**
    * Filter results by recency (90-day window)
+   *
+   * IMPORTANT: ChromaSync.queryChroma() returns deduplicated `ids` (unique sqlite_ids)
+   * but the `metadatas` array may contain multiple entries per sqlite_id (e.g., one
+   * observation can have narrative + multiple facts as separate Chroma documents).
+   *
+   * This method iterates over the deduplicated `ids` and finds the first matching
+   * metadata for each ID to avoid array misalignment issues.
    */
   private filterByRecency(chromaResults: {
     ids: number[];
@@ -174,10 +181,19 @@ export class ChromaSearchStrategy extends BaseSearchStrategy implements SearchSt
   }): Array<{ id: number; meta: ChromaMetadata }> {
     const cutoff = Date.now() - SEARCH_CONSTANTS.RECENCY_WINDOW_MS;
 
-    return chromaResults.metadatas
-      .map((meta, idx) => ({
-        id: chromaResults.ids[idx],
-        meta
+    // Build a map from sqlite_id to first metadata for efficient lookup
+    const metadataByIdMap = new Map<number, ChromaMetadata>();
+    for (const meta of chromaResults.metadatas) {
+      if (meta?.sqlite_id !== undefined && !metadataByIdMap.has(meta.sqlite_id)) {
+        metadataByIdMap.set(meta.sqlite_id, meta);
+      }
+    }
+
+    // Iterate over deduplicated ids and get corresponding metadata
+    return chromaResults.ids
+      .map(id => ({
+        id,
+        meta: metadataByIdMap.get(id) as ChromaMetadata
       }))
       .filter(item => item.meta && item.meta.created_at_epoch > cutoff);
   }