Normalize nopre -> QA (+ split AD/Enzyme)

[ChrisRackauckas-Claude]

Part of the fleet-wide nopre/NoPre test-group normalization (policy: standard QA checks live in a canonical QA group on ["lts", "1"], ubuntu-only; pre-incompatible functional tests get their own content-named groups).

Survey result for this repo: the NoPre group was PURE standard QA (Aqua + JET), so it merges into a canonical QA group:

• test/qa/: canonical layout — Project.toml (the former test/nopre/Project.toml + a [sources] path entry) and qa.jl folding the former test/qa.jl (Aqua) and test/test_jet.jl (JET) verbatim.
• test/runtests.jl: dispatches on GROUP == "QA" (drops the NoPre/Quality aliases and the runtime prerelease guard — the version matrix controls where QA runs).
• test/test_groups.toml: [NoPre] (which wrongly listed "pre"; the runtime guard made that CI cell a vacuous green) → [QA] on ["lts", "1"], ubuntu-only.

Verification: static only (TOML parse of test_groups.toml + qa/Project.toml; Meta.parseall of changed .jl files; Runic check clean). Test suites not run locally — CI should confirm the QA group goes green.

Ignore until reviewed by @ChrisRackauckas.

[ChrisRackauckas-Claude]

Branch reset to a clean implementation off the current default branch: removed unrelated changes from the prior revision (no spurious action/codecov version edits), renamed the dep env test/nopre -> test/qa, and kept the existing JET/Aqua test files in place (no test-logic changes). Static-verified locally: test_groups.toml parses and runtests.jl passes Meta.parseall.