Convert last remaining Python CI scripts to TypeScript

[mbg]

This PR converts the last remaining Python scripts that are used in our CI to TypeScript equivalents.

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.

Which use cases does this change impact?

Environments:

• Testing/None - This change does not impact any CodeQL workflows in production.

How did/will you validate this change?

• Unit tests - I am depending on unit test coverage (i.e. tests in .test.ts files).

If something goes wrong after this change is released, what are the mitigation and rollback strategies?

• Development/testing only - This change cannot cause any failures in production.

How will you know if something goes wrong after this change is released?

• Other - CI only.

Are there any special considerations for merging or releasing this change?

• No special considerations - This change can be merged at any time.

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

Converts CI changelog tooling from Python to TypeScript and updates workflows accordingly.

Changes:

• Adds TypeScript changelog utilities and tests.
• Replaces Python script invocations with tsx.
• Removes obsolete Python setup and scanning.

Show a summary per file

File	Description
pr-checks/util.ts	Adds error formatting helper.
pr-checks/rollback-changelog.ts	Adds rollback changelog CLI.
pr-checks/rollback-changelog.test.ts	Tests rollback generation.
pr-checks/prepare-changelog.ts	Adds changelog extraction CLI.
pr-checks/prepare-changelog.test.ts	Tests changelog extraction.
pr-checks/config.ts	Adds bundle release URL prefix.
pr-checks/changelog.ts	Adds parsing and rendering utilities.
pr-checks/changelog.test.ts	Tests changelog round-tripping.
pr-checks/bundle-changelog.ts	Adds bundle changelog CLI.
pr-checks/bundle-changelog.test.ts	Tests bundle changelog behavior.
.github/workflows/update-supported-enterprise-server-versions.yml	Removes unused Python setup.
.github/workflows/update-bundle.yml	Uses TypeScript bundle script.
.github/workflows/script/rollback_changelog.py	Removes superseded Python script.
.github/workflows/script/prepare_changelog.py	Removes superseded Python script.
.github/workflows/script/bundle_changelog.py	Removes superseded Python script.
.github/workflows/rollback-release.yml	Uses TypeScript changelog scripts.
.github/workflows/post-release-mergeback.yml	Uses TypeScript preparation script.
.github/workflows/codeql.yml	Removes Python analysis.
.github/actions/release-initialise/action.yml	Removes Python dependencies.

Review details

• Files reviewed: 19/19 changed files
• Comments generated: 2
• Review effort level: Medium