feat(#830): revoke leases across compaction lifecycle

packages/mosaic/framework/tools/lease-broker/mutator-gate.py

@@ -12,6 +12,8 @@ from collections.abc import Callable, Mapping, Sequence
 from pathlib import Path
 from typing import BinaryIO, Final
 
+from lease_generation import read_runtime_generation
+
 MAX_FRAME: Final = 64 * 1024
 BROKER_TIMEOUT_SECONDS: Final = 1.5
 
@@ -64,6 +66,7 @@ def main(
     environ: Mapping[str, str] | None = None,
     stream: BinaryIO | None = None,
     request: Callable[[Path, dict[str, object]], dict[str, object]] = broker_request,
+    resolve_generation: Callable[[Mapping[str, str]], int] = read_runtime_generation,
 ) -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument("--runtime", required=True, choices=("claude", "pi"))
@@ -74,9 +77,7 @@ def main(
         tool_name = read_tool_name(stream)
         socket_value = source_environment["MOSAIC_LEASE_BROKER_SOCKET"]
         session_id = source_environment["MOSAIC_LEASE_SESSION_ID"]
-        generation = int(source_environment["MOSAIC_RUNTIME_GENERATION"])
-        if generation < 0:
-            raise ValueError("INVALID_GENERATION")
+        generation = resolve_generation(source_environment)
         reply = request(
             Path(socket_value),
             {