Allow selected task environment variables

.gitignore

@@ -1 +1,3 @@
 local/
+__pycache__/
+*.py[cod]

python-tools/app/runner.py

@@ -339,6 +339,18 @@ class RunManager:
         }
         if self.settings.timezone_name:
             environment["TZ"] = self.settings.timezone_name
+        for name in os.environ.get("SERVER_MAINTENANCE_TASK_ENV", "").split(","):
+            name = name.strip()
+            if not name:
+                continue
+            if not name.isidentifier() or name.startswith("SERVER_MAINTENANCE_"):
+                raise ValueError(
+                    "SERVER_MAINTENANCE_TASK_ENV entries must be environment variable names "
+                    "outside the SERVER_MAINTENANCE_ namespace"
+                )
+            value = os.environ.get(name)
+            if value is not None:
+                environment[name] = value
         return environment
 
     def _upload_root(self, run_id: int) -> Path: