ci: drop workflow_dispatch and collapse duplicate release deploys

Address review:

- Remove workflow_dispatch. It defaults to running on main, which would deploy
  *unreleased* docs to production — reintroducing the problem this change fixes.
  A failed Pages deploy can be re-run via GitHub's "Re-run jobs" on the release
  run, which keeps the release tag's commit as the checkout context.
- Set concurrency cancel-in-progress: true so a version bump that publishes
  several Releases at once (each firing release: published for the same commit)
  collapses into a single Pages deploy instead of N identical ones.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: btravers

.github/workflows/deploy-docs.yml

@@ -1,21 +1,21 @@
 name: Deploy Documentation
 
 # Publish docs when a version is released (changesets creates a GitHub Release on publish), so the
-# site documents the latest *released* library rather than every commit on main. `workflow_dispatch`
-# is a manual redeploy escape hatch for docs-only fixes between releases.
+# site documents the latest *released* library rather than every commit on main.
 on:
   release:
     types: [published]
-  workflow_dispatch:
 
 permissions:
   contents: read
   pages: write
   id-token: write
 
 concurrency:
+  # A version bump can publish several Releases at once (monorepo); collapse that burst of events
+  # for the same commit into a single Pages deploy — the latest run cancels earlier ones.
   group: pages
-  cancel-in-progress: false
+  cancel-in-progress: true
 
 env:
   FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true