chore: tophat builds for PR scope

[maxy-shpfy]

Description

Contributes to https://github.com/Shopify/oasis-frontend/issues/180

Added a GitHub workflow that automatically triggers Tophat builds in the oasis-frontend repository when pull requests are opened or updated. The workflow extracts PR information (branch, number, SHA), makes a Buildkite API call to trigger the build, and posts a comment on the PR with instructions on how to tophat the changes using a URL parameter.

Related Issue and Pull requests

Type of Change

• Bug fix
• New feature
• Improvement
• Cleanup/Refactor
• Breaking change
• Documentation update

Checklist

• I have tested this does not break current pipelines / runs functionality
• I have tested the changes on staging

Screenshots (if applicable)

Tophat Links Demo - v1.mp4 (uploaded via Graphite)

Test Instructions

1. Create a test pull request to verify the workflow triggers
2. Check that the workflow runs and successfully makes the Buildkite API call
3. Verify that a comment is posted on the PR with tophat instructions
4. Confirm the comment includes the correct branch name and SHA for the tophat URL parameter

Additional Comments

This workflow requires the BUILDKITE_BEARER, and BUILDKITE_PIPELINE secrets to be configured with appropriate permissions to trigger builds in Buildkite. The workflow runs on all file changes in pull requests and provides developers with an automated way to test their changes on the staging environment.

[maxy-shpfy]

• poc: consolidated settings page #1847
• chore: tophat builds for PR scope #1841 👈 (View in Graphite)
• chore: emit vite manifest to support tophatting #1851
• master

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[github-actions]

🎩 To tophat this PR:

You can add the following URL parameter to your browser to tophat this PR:

`?tophat_location=02-22-chore_tophat_builds_for_pr_scope/2d2a9c5`

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