Fix auto-memory vector dedup dropping a user's fact on cross-tenant match

extract_and_store dedups each extracted fact against the vector store
before the (owner-scoped) text fallback. The vector store is a single
shared ChromaDB collection storing only {"source": "memory"} — no
owner — and find_similar queries it with no owner filter, so it can
return a memory_id belonging to a different tenant. The old code
continue'd (skipped storing) on any vector hit without checking
ownership, so when ChromaDB is healthy (the common path) a user's
freshly-extracted fact was silently dropped because it was merely
semantically similar to another user's memory — the text fallback that
IS owner-scoped never ran. Gate the skip on the matched memory being
this user's own (or legacy unowned), mirroring the text dedup predicate;
cross-tenant or stale matches fall through. Same bug class as #1743.

services/memory/memory_extractor.py

@@ -345,8 +345,17 @@ async def extract_and_store(
                     logger.warning(f"Memory dedup (vector) unavailable, using text fallback: {e}")
                     existing_id = None
                 if existing_id:
-                    logger.debug(f"Memory dedup (vector): '{fact_text[:50]}' matches {existing_id}")
-                    continue
+                    # The vector store is a single shared collection with no
+                    # owner metadata, so find_similar can return ANOTHER
+                    # tenant's memory. Only treat it as a duplicate when the
+                    # match is this user's own (or a legacy unowned) memory —
+                    # otherwise the user's freshly-extracted fact would be
+                    # silently dropped. Mirror the owner predicate used by the
+                    # text dedup below; cross-tenant/stale matches fall through.
+                    _match = next((e for e in existing if e.get("id") == existing_id), None)
+                    if _match is not None and (_match.get("owner") == _owner or _match.get("owner") is None):
+                        logger.debug(f"Memory dedup (vector): '{fact_text[:50]}' matches {existing_id}")
+                        continue
 
             # Text dedup fallback: exact match + fuzzy similarity
             user_existing = [e for e in existing if e.get("owner") == _owner or e.get("owner") is None] if _owner else existing