[BUG]: Dynamo does not refresh destination env with snapshot-restore-proxy #18164

Describe the Bug

The common Snapshot restore integration expects restore-context.json to have been written by maybe_run_restore_standby_mode() in the destination container. Snapshot's snapshot-restore-proxy can bypass that Python entrypoint. The restored process then either fails because the context file is absent or risks reusing capture-time Pod/discovery settings from an existing file.

Expected Behavior

Read the verified destination snapshot-restore-proxy environment and apply its allowlisted settings directly before the common runtime refresh, clearing capture-time settings that are absent at the destination. The proxy path should not read or write restore-context.json. Preserve the legacy standby-file handoff and support container restore within the same Pod and custom control-directory mounts. Ignore existing context files when using the proxy.

Scope

Keep this in the shared backend restore integration. Confirm the proxy identity/environment contract against ai-dynamo/snapshot; avoid assumptions tied to a model, storage system, or qualification workload.

Related: #15556 changes legacy restore-entrypoint admission; it does not refresh destination settings from snapshot-restore-proxy. #16580 monitors a restored standby after runtime configuration. Neither fixes this handoff.