fix: Add CREATE EXTENSION vector to migration 0104

alembic/versions/0104_add_embedding_and_audit_timestamps.py

@@ -19,6 +19,9 @@ down_revision = "0103"
 def upgrade() -> None:
     conn = op.get_bind()
 
+    # 0. Ensure pgvector extension is installed
+    op.execute("CREATE EXTENSION IF NOT EXISTS vector")
+
     # 1. Add embedding column to contacts (if not exists)
     result = conn.execute(sa.text(
         "SELECT column_name FROM information_schema.columns "