Stop passing the deleted active field in the signal fixture

RunStateHandle dropped its own active flag in favor of handle
presence as the sole liveness signal, but this fixture still set
it. tsconfig excludes tests/ from typecheck, so nothing caught
the stale field and the setter silently ignored the excess
property.

Author: TheGreatAxios

tests/fixtures/crash-run/simulate-signal.ts

@@ -26,7 +26,7 @@ await saveState(cwd, sessionId, {
   model,
 });
 
-setActiveRun({ sessionId, cwd, active: true, task, startedAt, model });
+setActiveRun({ sessionId, cwd, task, startedAt, model });
 installSignalHandlers();
 
 process.stdout.write(`${sessionDir(cwd, sessionId)}\n`);