PR checks: support collections of workflows

[mbg]

This is a sort-of experimental idea that I had in the context of #3028 where we bump the Go version in the workflows to a release candidate for testing purposes, but such PRs don't have to be merged anymore because the existing constraint of >= 1.22 would include allow new version once it is fully released.

This PR updates the sync.py script to allow "collections" of PR checks that can be triggered manually, with specific inputs. So instead of creating a PR that bumps the Go version for testing purposes only, we could instead just dispatch the collection workflow with the desired Go version.

Risk assessment

For internal use only. Please select the risk level of this change:

• Low risk: Changes are fully under feature flags, or have been fully tested and validated in pre-production environments and are highly observable, or are documentation or test only.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Consider adding a changelog entry for this change.
• Confirm the readme and docs have been updated if necessary.

[Copilot]

Pull Request Overview

This PR adds support for collections of workflows in the PR checks system. It allows grouping related workflow checks (like Go-related checks) into collections that can be executed together.

• Adds collection functionality to the PR checks sync script
• Introduces workflow inputs for parameterizing check execution
• Creates a consolidated "go" collection containing all Go-related checks

Reviewed Changes

Copilot reviewed 64 out of 64 changed files in this pull request and generated 1 comment.

File	Description
pr-checks/sync.py	Main implementation adding collection support and workflow input handling
pr-checks/checks/go-*.yml	Go check specifications updated with collection membership and inputs
.github/workflows/__go.yml	New generated collection workflow for running all Go checks together
.github/workflows/__*.yml	Generated workflow files updated with workflow_call and workflow_dispatch inputs

[henrymercer]

Nice! I like this. There is a little bit of awkwardness in the "go-version" input not being used in any of the steps, but it's not blocking.

[mbg]

I manually dispatched a run of __go.yml with a Go RC as input to check that all works as expected with the workflow_dispatch and workflow_call triggers: https://github.com/github/codeql-action/actions/runs/16963696649

[henrymercer]

Looks great. Thanks for the extra cleanup!