Clean catalog legacy and align documentation with the simplified architecture #57

Context

The current github-workflows tree contains documentation and generated files that reflect earlier architecture decisions.

Examples include:

• documentation saying github-workflows is the source of truth;
• workflow-family-decisions.md describing release-nextcloud-app.yml as cataloged although the current catalog no longer lists it;
• a retired release-nextcloud-app.yml generated template still present on disk;
• release documentation that should move to release-tool.

Goal

Carry only current organization-catalog responsibilities into this repository and remove obsolete architecture/documentation rather than copying it forward.

No-legacy rule

Migration is not a preservation exercise. Files, workflows, scripts, manifests, tests, documentation, compatibility paths, or generated outputs that are no longer part of the intended architecture must be deleted from the source repository rather than copied to .github.

In particular, workflow-templates/release-nextcloud-app.yml is retired, is not present in the current catalog manifest, and must be removed from github-workflows; it must not be migrated to this repository.

The same rule applies to any other stale artifact discovered during the migration.

Requirements

• Reconcile the catalog manifest, template directory and documentation.
• Delete retired release templates and their metadata/tests/references from github-workflows; do not migrate them.
• Identify other files that are only remnants of superseded designs and delete them rather than carrying them forward.
• Move release-product documentation to release-tool.
• Keep organization-level documentation for workflow adoption, upstream adaptation, dependency policy and cross-repository synchronization here.
• Update terminology so .github is the source of truth rather than a publication target.
• Review all migrated documentation against the resulting implementation after migration.
• Finish with a repository-wide search for stale architecture names, retired workflows and obsolete compatibility paths.

Done when

• this repository describes only the architecture that actually runs;
• no retired workflow or legacy compatibility artifact was migrated merely because it existed in github-workflows;
• obsolete source files have been removed from github-workflows;
• documentation contains no obsolete github-workflows publication model.