Canonical CI: grouped-tests.yml + root test/test_groups.toml

[ChrisRackauckas-Claude]

Summary

Converts the root test workflow (Tests.yml) into a thin caller of the canonical SciML reusable grouped-tests.yml@v1, with the test matrix declared once in a root test/test_groups.toml.

Before: Tests.yml hand-maintained a version × os matrix ({1, lts} × {ubuntu, macos, windows} = 6 cells) and called tests.yml@v1 directly.

After:

• Tests.yml jobs.tests is now just:

  jobs:
    tests:
      uses: "SciML/.github/.github/workflows/grouped-tests.yml@v1"
      secrets: "inherit"

• test/test_groups.toml declares a single All group:

  [All]
  versions = ["1", "lts"]
  os = ["ubuntu-latest", "macos-latest", "windows-latest"]

The name: "Tests", on: triggers, and concurrency: block are preserved verbatim, so the existing branch-protection status check is unchanged. No with: inputs are needed — all of group-env-name (GROUP), check-bounds (yes), coverage (true), coverage-directories (src,ext), and apt-packages match the reusable workflow defaults and the old job's behavior.

Why a single All group

This repo's test/runtests.jl dispatches with const GROUP = get(ENV, "GROUP", "All") and runs QA whenever GROUP != "Core"; the functional testsets always run. The old Tests.yml never set GROUP, so every cell ran the full suite (QA + functional) under the default All. A single All group reproduces that exactly: GROUP=All → QA + all functional tests in one job per cell. runtests.jl is unchanged; QA is not isolated in this repo's dispatch, so a Core/QA split would either drop QA (Core excludes it) or duplicate the functional tests, neither of which reproduces the old matrix.

Matrix match

Verified with scripts/compute_affected_sublibraries.jl . --root-matrix (from SciML/.github@v1). Emitted set:

group	version	os
All	1	ubuntu-latest
All	1	macos-latest
All	1	windows-latest
All	lts	ubuntu-latest
All	lts	macos-latest
All	lts	windows-latest

6/6 exact on (version, os), each cell running the identical full suite as before.

QA

QA (Aqua + JET) already exists in test/qa.jl and runs under this matrix as before. Per Category A, no local Aqua/JET run was performed and runtests.jl was not modified. Project.toml metadata was checked statically: julia compat floor is already "1.10" (LTS), every [targets].test entry is declared in [extras], every dep/extra has a [compat] entry, and there are no stale extras — no benign-metadata fixes were needed.

YAML and TOML both parse cleanly (static-verified).

Ignore until reviewed by @ChrisRackauckas.