fix(morph): publish opengauss alias from tracked template source

[gauss-math-inc]

Summary

• check the OpenGauss Morph template into the repo as the source of truth
• replace the opaque alias refresh workflow with an explicit publisher script
• publish by creating and caching a fresh template from tracked YAML, then replacing the alias once the new template is ready
• add focused tests for the Morph publish flow

Validation

• uv run --no-project --with pytest python -m pytest -o addopts='' tests/test_publish_shared_template.py -q
• python3 -m py_compile scripts/publish_shared_template.py tests/test_publish_shared_template.py
• live Morph API probes against disposable aliases showed:
  • share is create-only and cannot reuse an existing alias
  • shared templates are immutable and cannot be edited in place
  • deleting the old shared template frees the alias name
  • creating and caching a fresh tracked template works against the live API
  • sharing a ready template to a new alias works against the live API

Why this shape

The old workflow called POST /api/templates/aliases/{alias}/refresh, which rebuilds whatever Morph already has stored for that alias. That is exactly how the live morph.new/opengauss template drifted away from the repo and regressed into the extra setup-question flow.

The new workflow makes the repo-owned YAML authoritative again.