ci: draft pull requests start no run; marking one ready does

CI and the packaging lint listen for ready_for_review too, and their
pull-request jobs skip drafts, so a contributor's work in progress no
longer takes runners from develop and the release.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

.github/workflows/packaging-lint.yml

@@ -9,6 +9,8 @@ on:
     branches: [develop]
     paths: [".github/workflows/**", "packaging/**"]
   pull_request:
+    # A draft starts no run; marking it ready for review does.
+    types: [opened, synchronize, reopened, ready_for_review]
     paths: [".github/workflows/**", "packaging/**"]
   workflow_dispatch:
 
@@ -22,6 +24,7 @@ concurrency:
 jobs:
   lint:
     name: Packaging lint
+    if: github.event_name != 'pull_request' || !github.event.pull_request.draft
     runs-on: ubuntu-24.04
     timeout-minutes: 10
     env: