Auto-draft release notes from GitLab to Notion and Slack

Build an agent workflow that drafts and publishes release notes whenever I publish a new release in GitLab.

Trigger: a GitLab webhook on the project's Release Hook event. The webhook payload includes the project id, the new release tag, the release name, the release description, and the released_at timestamp. The agent should only run on action == "create".

What the agent should do, step by step:

1. Read the incoming Release Hook payload to get the project id, the new tag name, and the released_at timestamp.

2. Call GitLab List Releases for the same project, sorted by released_at descending, and find the most recent release whose tag is not the new one. Treat that release's released_at as the start of the merge window. If there is no prior release, use the project's creation date as the start instead.

3. Call GitLab List Project Merge Requests with state=merged, scope=all, and updated_after / updated_before (or merged window) bounded by the prior release's released_at and the new release's released_at. Paginate until exhausted.

4. For each merged MR, call GitLab Get a Single Merge Request to read the full title, description, author, and labels. Look for a Jira issue key in the title or description using the pattern of uppercase letters, a dash, and digits (e.g. ABC-1234). If a key is found, call Jira Get Issue with that key and grab the summary so the human-readable feature name can be used instead of the raw MR title.

5. Group the resulting entries into three buckets: Features, Fixes, and Chores. Use the MR title prefix or labels to decide (feat / feature -> Features, fix / bug -> Fixes, chore / deps / refactor / ci -> Chores). When in doubt, default to Features. Draft a short two or three sentence headline summary of the release in product-marketing tone, naming the biggest user-visible improvement.

6. Call Notion Create a Page under a configured Release Notes parent page. The page title should be the release tag and name (for example "v2.4.0 - Faster onboarding"). Then call Notion Update Page Content as Markdown on the new page with the body: headline summary, then a Features section, then Fixes, then Chores. Each entry should be a bullet with the friendly name (from Jira summary when available, otherwise the MR title) and a link to the GitLab MR.

7. Call Slack Send a Message in the configured release-announcements channel. The message should have the release title, a one-line summary, the top three highlights (pick from Features first, then Fixes, skipping anything in the Chores bucket), and a link to the new Notion page. Keep the Slack message short. The Notion page is the long form.

Inputs to ask me for on first run:

- The GitLab project (id or path) and a credential to read it.

- The Notion parent page id where the release notes archive should live.

- The Slack channel for the announcement.

- Whether Jira lookups should run, and if so, the Jira workspace credential.

Rules: keep dependency-bump and chore MRs out of the Slack highlights, but include them in the Notion page so the changelog is complete. If a release fires twice for the same tag, do not create a duplicate Notion page or repost to Slack.