feat: reserve downloads and protect slot cleanup

controller/store.py

@@ -1195,6 +1195,23 @@ class ControllerStore:
             )
             return True
 
+    def pending_deletions(self) -> list[DeleteToken]:
+        with self._lock:
+            rows = self.connection.execute(
+                """
+                SELECT slot_number, generation FROM slots
+                WHERE media_state = 'deleting' ORDER BY slot_number
+                """
+            ).fetchall()
+            return [
+                DeleteToken(
+                    slot=row["slot_number"],
+                    generation=row["generation"],
+                    reason="recovered_interrupted_deletion",
+                )
+                for row in rows
+            ]
+
     def begin_expired_deletions(self, now: float | None = None) -> list[DeleteToken]:
         now = self._now() if now is None else now
         tokens: list[DeleteToken] = []