docs: expose and verify release identity in rendered HTML #48

Problem

The rendered documentation does not expose the standard ML4T release identity meta tags. A strict local build with ML4T_DOCS_VERSION=0.1.3 and ML4T_DOCS_COMMIT=96a531185d774b375576470b15344bd2bdba5435 produces HTML without ml4t-library, ml4t-version, or ml4t-commit. The deployment currently verifies only release.json, so this omission passed release qualification.

Expected behavior

Every rendered documentation page exposes:

• ml4t-library=models
• the package version in ml4t-version
• the full release commit in ml4t-commit

Strict docs CI fails if any rendered page omits or mismatches those values. Release verification also checks the deployed stable and versioned HTML pages.

Acceptance criteria

• Add the three standard meta tags to the shared page template.
• Add behavior-level verification over rendered HTML.
• Run that verification in the ordinary docs CI job and release workflow.
• Extend deployed documentation verification to cover both stable and versioned HTML.
• Prepare the next patch release required to deploy the truthful identity.