Point release-publish-mechanics.md's File-Target Bullet at the build-release-asset Hook #2323

Problem

.agents/skills/branching-and-release-model/references/release-publish-mechanics.md, under "Files attached to the GitHub Release", says:

A data-only repo's own output (e.g. a symbol library) is not yet expressible as a hub hook or an enable_* input, so it stays a carried leaf until the hub task grows one.

#2295 added exactly that. build-release-task.yml now has the enable_release_asset input and the build-release-asset hook, released in 2.0.807. WORKFLOW.md section 3 and docs/reusable-workflows.md Stage 4 already describe the hook. This reference was not updated, so it still tells a repo with a file target to keep a carried leaf. The generated copies under .github/skills/ and .claude-plugin/ carry the same sentence.

Fix

Replace the sentence with a pointer to the build-release-asset hook and enable_release_asset: true, as the hook's own docs describe it, then regenerate the distributions.

Found while ptr727/homeassistant-purpleair adopted the hook for its HACS zip (ptr727/homeassistant-purpleair#365).