Fix hosted production backup ID example

[SoundBlaster]

Summary

• Correct the hosted production backup ID example so it satisfies the runtime contract.
• Link related issue/task (if any): production-profile ARM64 rehearsal follow-up.

Motivation

• The documented command emitted uppercase T and Z, while BACKUP_ID_PATTERN accepts lowercase identifiers only.
• The mismatch caused the first rehearsal backup to fail before writing data.

Goals

• Keep the documented production command executable against the validated runtime contract.
• Production deployment and canary sign-off remain out of scope.

Changes

• Generate lowercase timestamp separators in the runbook backup ID.
• Add a regression tying the documented example to the runtime pattern.

Validation

• Tests added/updated for changed behavior
• Local checks passed

Commands run:

.venv/bin/python -m unittest tests.test_hosted_managed_production -v
make python-quality
git diff --check

Results:

• Focused production tests: 15 passed.
• Full Python quality suite: 355 passed, 7 skipped.

Risks / Notes

• Backward compatibility impact: none; valid existing backup IDs are unchanged.
• Migration/config changes required: none.
• Known limitations: this fixes the runbook drift only.

Checklist

• PR title clearly describes the change
• Scope is focused and minimal
• Documentation updated (or N/A)
• Workflow/artifact changes distinguish artifact presence from readiness/status
• Temporary or intermediate paths are scoped to the current run/task where relevant
• No secrets or sensitive data added