[kylan11]

Summary

• Bump the chart, application version, and Artifact Hub image metadata to 0.4.5.
• Summarize the sentinel startup, stand-in availability, bounded hold, multi-replica signal, and dependency fixes from Stop passing the removed --mode flag to the sentinel #7–Run the node signal adapters on every replica, not only the leader #11.
• Document the upgrade and unchanged CRD schema.

Thanks to @0xmichalis for the fixes and regression coverage.

Verification

• The contributing PRs passed build, lint, unit/envtest, Helm, and isolated Kind E2E CI.
• The combined implementation passed local make test lint build and startup without the optional Rollout API.
• Release chart arguments, metadata, Helm lint, sentinel-enabled rendering, and packaging pass.
• The CRD schema is unchanged from v0.4.4.

The release will publish the multi-architecture image, OCI Helm chart, and GitHub release after this PR's checks pass.