fix: deduplicate memories on save with exact-match check

Prevents inserting a memory if an identical one already exists for the
user. Also cleaned up 30 anonymized and 4 duplicate memories from DB.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

utils/database.py

@@ -542,6 +542,14 @@ class Database:
         conn = self._connect()
         try:
             cursor = conn.cursor()
+            # Skip if an identical memory already exists for this user
+            cursor.execute(
+                "SELECT COUNT(*) FROM UserMemory WHERE UserId = ? AND Memory = ?",
+                user_id, memory[:500],
+            )
+            if cursor.fetchone()[0] > 0:
+                cursor.close()
+                return
             cursor.execute(
                 """INSERT INTO UserMemory (UserId, Memory, Topics, Importance, ExpiresAt, Source)
                    VALUES (?, ?, ?, ?, ?, ?)""",