Make migration 24 idempotent

surfsense_backend/alembic/versions/24_fix_null_chat_types.py

@@ -7,6 +7,8 @@ Revises: 23
 
 from collections.abc import Sequence
 
+import sqlalchemy as sa
+
 from alembic import op
 
 # revision identifiers, used by Alembic.
@@ -16,11 +18,27 @@ branch_labels: str | Sequence[str] | None = None
 depends_on: str | Sequence[str] | None = None
 
 
+def table_exists(table_name: str) -> bool:
+    """Check if a table exists in the database."""
+    conn = op.get_bind()
+    result = conn.execute(
+        sa.text(
+            "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = :table_name)"
+        ),
+        {"table_name": table_name},
+    )
+    return result.scalar()
+
+
 def upgrade() -> None:
     """
     Fix any chats with NULL type values by setting them to QNA.
     This handles edge cases from previous migrations where type values were not properly migrated.
     """
+    # Skip if chats table doesn't exist (fresh database)
+    if not table_exists("chats"):
+        return
+
     # Update any NULL type values to QNA (the default chat type)
     op.execute(
         """