fix(ci): trigger release build on release publish, not tag push

semantic-release creates the tag via the GitHub Releases API
(@semantic-release/github). API-created tags don't emit the
refs/tags/* push event that 'on: push: tags' listens for, so the
artifact build never auto-ran — every release so far was built by
manual workflow_dispatch.

The PAT-published release does fire 'release: published', so trigger on
that. workflow_dispatch stays as a manual fallback.

Author: offendingcommit

.github/workflows/release.yml

@@ -1,9 +1,8 @@
 name: Release
 
 on:
-  push:
-    tags:
-      - 'v*'
+  release:
+    types: [published]
   workflow_dispatch:
     inputs:
       tag: