fix(release): publish latest RDF asset and align W3ID documentation

[pedropaulofb]

Summary

Update the OntoUML/UFO Catalog release publication workflow and documentation to align the repository with the W3ID redirects merged in perma-id/w3id.org#6663.

This PR:

• publishes both the version-specific and latest catalog Turtle assets for newly created releases;
• validates that both assets are non-empty, byte-identical, and parseable as Turtle;
• uploads both assets as workflow artifacts and attaches both to the GitHub Release;
• documents the distinction between release pages, version-specific Turtle assets, and the moving latest Turtle alias;
• documents the canonical W3ID entry points for the catalog, FDP, models, and releases.

Release assets

For each newly created release, the workflow publishes:

• ontouml-models-YYYYMMDD.ttl — the version-specific aggregated RDF asset;
• ontouml-models-latest.ttl — a byte-identical moving alias for the latest published release.

The latest asset is intended for convenient access and is not an immutable snapshot. Reproducible use should reference a dated release and its commit.

The generated assets contain aggregated model and catalog RDF. They do not replace the GitHub source archive and do not contain native Visual Paradigm projects, JSON files, images, or bibliographies.

W3ID route correspondence

W3ID entry point	Meaning
https://w3id.org/ontouml-models	Catalog landing page redirecting to the GitHub repository
https://w3id.org/ontouml-models/fdp/	Legacy FAIR Data Point catalog page
https://w3id.org/ontouml-models/models/{slug}	GitHub page for a canonical model directory
https://w3id.org/ontouml-models/models/{slug}/{path}	Raw GitHub file below a model directory
https://w3id.org/ontouml-models/release	Latest GitHub release page
https://w3id.org/ontouml-models/release/latest.ttl	Latest aggregated Turtle asset
https://w3id.org/ontouml-models/release/YYYYMMDD	Specific GitHub release page
https://w3id.org/ontouml-models/release/YYYYMMDD.ttl	Version-specific aggregated Turtle asset

The corresponding redirect implementation is already provided by W3ID PR #6663. This PR updates the OntoUML models repository and does not modify the W3ID configuration.

Validation

• The branch was compared against the current master branch.
• The release workflow creates the dated asset and the latest alias from the same generated file.
• The workflow checks byte identity with cmp.
• Both files are independently parsed as Turtle with RDFLib.
• The current 20260831 release contains both expected assets with identical SHA-256 digests.
• No model-content or catalog-data changes are included.