docs(deploy): add sandbox deploy runbook and recreate-relay script

[Ferryx349]

Description

Document the manual post-pull migrate and recreate flow, rollback steps, and /readyz verification. Closes the gap where the webhook pull stack loads images but does not restart the relay.

Related Issue

closes:- #767

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Non-functional change (docs, style, minor refactor)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my code changes.
• I added a changeset, or this is docs-only and I added an empty changeset.
• All new and existing tests passed.

[changeset-bot]

🦋 Changeset detected

Latest commit: da7ac54

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