v0.4.0

• Optional .pr-steward.json (workingBranch, defaultReviewer, mergeStrategy) read by open-pr, merge-pr and release; see reference/config.md.
• CI: check_catalog.py checks changelog dates and version order.
• new-issue asks once for an optional reference link (Jira, Confluence, docs) and adds a ## References section; issue templates get the same optional field.
• CI: dependabot-automerge.yml enables auto-merge on Dependabot semver-patch PRs; minor and major stay manual.
• setup-ci: optional notify piece posts merged PRs/MRs and releases to Mattermost, Slack or Telegram through a NOTIFY_WEBHOOK_URL secret.
• merge-pr: runs tick-checklist before the merge and fixes a closed issue with unticked items after it. tick-checklist is idempotent so merge-pr can call it.
• setup-ci: dry-run step lists each file to create or change with its diff and writes nothing until the user confirms.
• open-pr: look up an existing PR/MR for the branch and issue before creating one; update and reuse it when found.
• merge-pr: read mergeability after checks; on conflict or behind, rebase, push with --force-with-lease and re-watch checks before merging.
• release skill: version bump, dated changelog, release PR, annotated tag and release notes on GitHub or GitLab.
• CI: README and reference/host-commands.md now carry real links, so the lychee job verifies something and no longer needs failIfEmpty: false.