ci: fix empty branch display in pre-release publish message

[Aaron ("AJ") Steers (aaronsteers)]

What

Fixes the empty "Branch:" field in pre-release connector publish messages. When /publish-connectors-prerelease is invoked (via slash command or MCP tool), the status comment shows Branch: `` instead of the actual branch name.

Example of the bug (from airbytehq/airbyte#71063):

Branch: ``

How

Simplified the workflow to always derive the git ref from the PR number:

1. Made pr a required input (was optional)
2. Use refs/pull/${{ inputs.pr }}/head inline for checkout and downstream publish_connectors.yml call
3. Changed comment display from Branch: ... to PR: #... with a clickable link
4. Added note to gitref input description that it's ignored (kept for slash command dispatch compatibility)

Key design decisions:

• PR number is the single source of truth - no fallback logic needed
• gitref input is kept but ignored (required by slash command dispatch static args)
• No GitHub API calls needed - refs/pull/{pr}/head is the canonical way to reference PR code

Review guide

1. .github/workflows/publish-connectors-prerelease-command.yml - All changes in this file

Human review checklist:

• Verify refs/pull/{pr}/head works correctly for checkout and downstream publish_connectors.yml
• Confirm the UX change from "Branch: ..." to "PR: #..." is acceptable
• Verify existing callers (slash command dispatcher, MCP tool) always pass PR number
• Consider if fork PRs need special handling (should work since refs/pull/{pr}/head is in the base repo)

User Impact

Pre-release publish status comments will now correctly display a clickable PR link instead of showing an empty branch value.

Can this PR be safely reverted and rolled back?

• YES 💚
• NO ❌

---

Link to Devin run: https://app.devin.ai/sessions/8a26b7fcb0234672aced61d260dd706d
Requested by: AJ Steers (Aaron ("AJ") Steers (@aaronsteers))

[devin-ai-integration]

Original prompt from AJ Steers

Received message in Slack channel #ask-devin-ai:

@Devin - The "branch" variable seems unset in the message here. Can you fix?
Thread URL: https://airbytehq-team.slack.com/archives/C08BHPUMEPJ/p1767292373665049

ATTACHMENT:"https://app.devin.ai/attachments/003d1097-e12b-47fc-af8a-969ec1e54411/image.png"

[devin-ai-integration]

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[github-actions]

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Helpful Resources

• Breaking Changes Guide - Breaking changes, migration guides, and upgrade deadlines
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• #connector-ci-issues
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PR Slash Commands

Airbyte Maintainers (that's you!) can execute the following slash commands on your PR:

• /format-fix - Fixes most formatting issues.
• /bump-version - Bumps connector versions.
  • You can specify a custom changelog by passing changelog. Example: /bump-version changelog="My cool update"
  • Leaving the changelog arg blank will auto-populate the changelog from the PR title.
• /bump-progressive-rollout-version - Bumps connector version with an RC suffix for progressive rollouts.
  • Creates a release candidate version (e.g., 2.16.10-rc.1) with enableProgressiveRollout: true
  • Example: /bump-progressive-rollout-version changelog="Add new feature for progressive rollout"
• /run-cat-tests - Runs legacy CAT tests (Connector Acceptance Tests)
• /run-regression-tests - Runs regression tests for the modified connector(s).
• /build-connector-images - Builds and publishes a pre-release docker image for the modified connector(s).
• /publish-connectors-prerelease - Publishes pre-release connector builds (tagged as {version}-preview.{git-sha}) for all modified connectors in the PR.
• Connector release lifecycle (AI-powered):
  • /ai-prove-fix - Runs prerelease readiness checks, including testing against customer connections.
  • /ai-canary-prerelease - Rolls out prerelease to 5-10 connections for canary testing.
  • /ai-release-watch - Monitors rollout post-release and tracks sync success rates.
• JVM connectors:
  • /update-connector-cdk-version connector=<CONNECTOR_NAME> - Updates the specified connector to the latest CDK version.
    Example: /update-connector-cdk-version connector=destination-bigquery
  • /bump-bulk-cdk-version bump=patch changelog='foo' - Bump the Bulk CDK's version. bump can be major/minor/patch.
• Python connectors:
  • /poe connector source-example lock - Run the Poe lock task on the source-example connector, committing the results back to the branch.
  • /poe source example lock - Alias for /poe connector source-example lock.
  • /poe source example use-cdk-branch my/branch - Pin the source-example CDK reference to the branch name specified.
  • /poe source example use-cdk-latest - Update the source-example CDK dependency to the latest available version.

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