Route umbrella QA group through the qa keyword (fixes GROUP=QA dispatch)

[ChrisRackauckas-Claude]

Problem

The tests / QA checks on main fail with:

ERROR: LoadError: ArgumentError: run_tests: GROUP="QA" was requested but no `qa` body was provided

The root test/runtests.jl registered the QA (Aqua/JET) group via
groups = Dict("QA" => (; env, body)). But "QA" is a reserved group
name in SciMLTesting's run_tests: when GROUP="QA", the dispatcher
routes to the qa keyword body, not through the groups table. With
qa left unset, the reserved-name branch throws the ArgumentError
above.

Fix

Pass the QA group via the qa = (; env, body) keyword instead of groups.
No other behavior changes; the QA env/body are unchanged
(test/qa/Project.toml + test/qa/qa.jl).

Local verification

On Julia 1.12 (the julia 1 matrix entry), GROUP=QA Pkg.test() now runs
the umbrella Aqua+JET suite cleanly:

Test Summary: | Pass  Total     Time
QA            |   12     12  1m58.8s
     Testing OptimalUncertaintyQuantification tests passed

Runic check (runic --check) passes on the edited file.

Scope / remaining reds (not addressed here)

This PR fixes the julia 1 QA check. Other main reds have different
root causes and are out of scope for this focused PR:

• tests / Core (julia lts) and tests / QA (julia lts) fail earlier, at
  julia-buildpkg, with expected package CanonicalMoments ... to be registered. On Julia 1.10 the [sources] table is not auto-resolved, and
  the centralized SciML/.github tests.yml skips its "Develop in-repo
  [sources] path deps" step when project == '.' — so a monorepo root
  project with in-repo [sources] never gets its path deps developed on
  1.10. That is a SciML/.github workflow bug, tracked separately.
• sublibraries / lib/OUQBase [QA] / lib/CanonicalMoments [QA] report real
  Aqua/JET findings (stale dep PolynomialRoots, a type-piracy on
  CanonicalMoments.RawMomentSequence, several JET errors). These are genuine
  code findings, not harness bugs.
• Downgrade / Downgrade Sublibraries fail because the downgrade resolver
  cannot handle the unregistered in-repo [sources] UUIDs.

Please ignore until reviewed by @ChrisRackauckas.

[ChrisRackauckas-Claude]

Status update (CI triage 2026-06-20): the tests / QA (julia 1) check this PR targets is now GREEN on this branch. Remaining reds are out of scope (separate root causes):

• sublibraries / [QA] real Aqua/JET findings: fixed by Fix sublibrary QA (Aqua/JET) findings in OUQBase and CanonicalMoments #27 (now green there).
• tests / Core (julia lts) + tests / QA (julia lts): centralized SciML/.github tests.yml did not develop the monorepo ROOT's in-repo [sources] on the LTS -> expected package CanonicalMoments ... to be registered. Fixed in tests.yml: develop in-repo [sources] for monorepo ROOT (project: '.') on the LTS .github#101 (verified locally).
• Downgrade / Downgrade Sublibraries: julia-actions/julia-downgrade-compat create_merged_project leaves path-[sources] deps in the merged base [deps] -> unknown package UUID. Reported upstream.