ci: automate RC releases; hotfix/* pushes no longer publish

Removes publish_hotfix_release: a hotfix/* branch push published a GA
release to Maven Central with no tag or review (QRun-IO/qbit-cdn#12,
QRun-IO/qqq#1121). hotfix/* branches now run test_only; a hotfix
release publishes from a reviewed vX.Y.Z tag through publish_release.
Adds .github/workflows/release-rc.yml (reusable QRun-IO/.github
qbit-release-rc): a manual dispatch, or merging a develop PR labelled
release:rc, merges develop into the release line and the release/* push
runs the existing CircleCI RC publish.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.circleci/config.yml

@@ -22,7 +22,7 @@ workflows:
               context: [qqq-maven-registry-credentials]
               filters:
                  branches:
-                    ignore: /(develop|release\/.*|hotfix\/.*)/
+                    ignore: /(develop|release\/.*)/
 
    publish_snapshot:
       jobs:
@@ -58,14 +58,3 @@ workflows:
                     ignore: /.*/
                  tags:
                     only: [/^v\d+\.\d+\.\d+$/]
-
-   publish_hotfix_release:
-      jobs:
-         - qqq-orb/mvn_publish:
-              pre-steps:
-                 - configure-package-install
-              context: [qqq-maven-registry-credentials]
-              branch_type: hotfix
-              filters:
-                 branches:
-                    only: [/hotfix\/.*/]

.github/workflows/release-rc.yml

@@ -0,0 +1,25 @@
+# Cut the next release candidate (QRun-IO/qqq docs/QRUN-QBIT-REPO-STANDARD.md, C6):
+# run this workflow by hand, or merge a develop PR labelled `release:rc`. It merges develop into
+# the release line and the release/* push runs CircleCI publish_release_candidate.
+name: Release candidate
+
+on:
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: Print the plan without merging or creating branches
+        type: boolean
+        default: false
+  pull_request:
+    types: [closed]
+    branches: [develop]
+
+permissions:
+  contents: write
+
+jobs:
+  release-rc:
+    if: github.event_name == 'workflow_dispatch' || (github.event.pull_request.merged == true && contains(github.event.pull_request.labels.*.name, 'release:rc'))
+    uses: QRun-IO/.github/.github/workflows/qbit-release-rc.yml@main
+    with:
+      dry_run: ${{ github.event_name == 'workflow_dispatch' && inputs.dry_run }}