Remove redundant docCache update (onChange already handles it)

Co-authored-by: naielv <109038805+naielv@users.noreply.github.com>

src/db.js

@@ -135,11 +135,9 @@ var DB = (function () {
       await local.put(doc);
 
       // FIX: manually trigger map() callbacks for local update
-      // Call onChange BEFORE updating docCache so that onChange can detect the change
+      // onChange will update docCache and notify all subscribers
       onChange({ doc: doc });
 
-      try { docCache[_id] = typeof doc.data === 'string' ? doc.data : JSON.stringify(doc.data); } catch (e) {}
-
     } catch (e) {
       console.error('DB.put error', e);
     }