…ady_for_review` before

`macos-latest-xlarge` now resolves to macOS 26, which ships only Xcode 26
(Swift 6.2) and no longer includes Xcode 16. The Swift-analysing PR checks
select Xcode 16 because CodeQL CLI versions before 2.24.0 only support Swift
up to 6.1, so `xcode-select -s /Applications/Xcode_16.app` fails on macOS 26.

Pin these checks to macOS 15, where Xcode 16 is still available, so we keep
testing the full matrix of supported CodeQL versions. This also pre-empts the
`swift-custom-build` check failing once plain `macos`/`macos-latest` migrates.

See actions/runner-images#14167.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Rather than pinning every macOS job to macOS 15, only run the older CodeQL CLI
versions (which need Xcode 16, and so macOS 15) there. Newer versions, which
support Swift 6.2, run on the latest macOS runner with its default Xcode, so we
keep exercising the common latest-CLI-on-latest-runner combination.

To express this, `sync.ts` now supports an optional per-OS-entry
`codeql-versions` filter, used by `multi-language-autodetect` to send old
versions to `macos-15-xlarge` and new versions to `macos-latest-xlarge`.

`swift-custom-build` only runs `linked`/`default`/`nightly`, which all support
Swift 6.2, so it no longer needs the Xcode 16 step or a macOS 15 pin.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Redesign the per-entry codeql-versions filter so an OS entry without a
version list catches all versions not claimed by its siblings. This lets
new CodeQL versions flow to macos-latest-xlarge automatically. Move
v2.23.9 (which supports Swift 6.2) off the macOS 15 list and simplify the
matrix filter logic.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Pin Swift macOS PR checks to macOS 15 for Xcode 16

Remove `ready_for_review` triggers from workflows