feat: add can_manage_script_template permission check

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

backend/app/core/permissions.py

@@ -169,3 +169,19 @@ def can_create_step_category(user: User, account_id: Optional[UUID]) -> bool:
     if user.account_role == "owner" and account_id == user.account_id and user.account_id is not None:
         return True
     return False
+
+
+def can_manage_script_template(user: User, template_created_by: Optional[UUID], template_account_id: Optional[UUID] = None) -> bool:
+    """Can the user edit/delete this script template?
+
+    - Super admins can manage any template
+    - Account owners can manage any template in their account
+    - Engineers can manage templates they created
+    """
+    if user.is_super_admin:
+        return True
+    if user.account_role == "owner" and template_account_id == user.account_id and user.account_id is not None:
+        return True
+    if template_created_by == user.id:
+        return True
+    return False