e2e: add controller recovery test

[ptalgulk01]

Summary

• Add TestControllerRecovery e2e test that verifies the controller recovers after being killed and completes a pending rollout
• The test scales the controller deployment to zero, patches the pool to a new image, then restores the controller and asserts the rollout completes

Context

Part of the e2e test planning in #69 (scenario 5: kill controller/daemon during rollout).

Manual testing also revealed that scenarios 4 (faulty node after reboot) and 8 (cross-distro bad image) both fail — the controller has no reboot timeout and doesn't correlate Node.Ready status, so nodes stuck after reboot are never marked degraded. Those need feature work before tests can be written.

Test plan

• make e2e V=1 RUN=TestControllerRecovery passes locally (159s)

[ptalgulk01]

/cc @alicefr @HarshwardhanPatil07