QA: run_qa v1.6 form + ExplicitImports

[ChrisRackauckas-Claude]

Ignore until reviewed by @ChrisRackauckas.

Brings this repo's QA onto the SciMLTesting 1.6 run_qa form and enables the ExplicitImports check group. Converts the hand-rolled test/qa/qa.jl (which carried two @test_broken placeholders) to a single declarative run_qa call.

What changed

• test/qa/qa.jl: manual Aqua/JET @testset -> run_qa(FiniteVolumeMethod1D; explicit_imports = true, ei_kwargs = ...).
• Aqua deps_compat (QA: Aqua/JET findings marked @test_broken pending fix #84): fixed at the source rather than marked broken — added SparseArrays = "1" to the root [compat]. Aqua.test_all (incl. deps_compat) now passes.
• JET (QA: Aqua/JET findings marked @test_broken pending fix #84): does not reproduce under run_qa's canonical config (mode = :typo, target_modules = (FiniteVolumeMethod1D,)). The original 4 reports were artifacts of target_defined_modules = true (whole-world analysis). JET.test_package now runs and passes, so no jet_broken is needed.
• test/explicit_imports.jl removed + ExplicitImports dropped from root [extras]/[targets].test and the test/ env. Its two checks are subsumed by the QA group's six; ExplicitImports is now transitive via SciMLTesting.
• test/qa/Project.toml: SciMLTesting compat "1" -> "1.6". SafeTestsets kept (the folder-model @safetestset wrapper needs it as a direct dep of the group env); Aqua/JET kept.

ExplicitImports findings summary

All 6 checks run. 4 pass clean (no_implicit_imports, no_stale_explicit_imports, all_explicit_imports_via_owners, all_qualified_accesses_via_owners). 2 carry documented ignore-lists for other packages' not-yet-public names (no own-package findings, nothing broken):

check	ignored name	source pkg	reason
all_qualified_accesses_are_public	AutoSpecialize	SciMLBase	specialization default in solve.jl
all_qualified_accesses_are_public	init	CommonSolve	CommonSolve.init extended/forwarded
all_explicit_imports_are_public	solve	CommonSolve	re-exported

These ignores can be dropped once the upstream packages mark those names public.

Verification

Run locally on Julia 1.10 against released SciMLTesting 1.6.0 (Pkg resolves it; no dev-from-branch) via the exact CI path (GROUP=QA through test/runtests.jl):

Test Summary: | Pass  Total   Time
QA/qa.jl      |   18     18  36.6s

18/18 pass, 0 fail / 0 error / 0 broken (11 Aqua sub-checks + 1 JET + 6 ExplicitImports).

Closes #84.

🤖 Generated with Claude Code

[ChrisRackauckas-Claude]

EI cleanup finished against the live make-public releases

Re-verified this PR's ExplicitImports cleanup against the now-registered public-API releases (SciMLBase 3.27.0, CommonSolve 0.2.9, SciMLTesting 1.7.0), no dev of base libs (FVM dev'd via [sources]):

Source migration: none needed. src/ has zero DiffEqBase.X accesses; it already uses SciMLBase.ODEProblem / SciMLBase.AutoSpecialize and CommonSolve.init directly. SciMLBase + CommonSolve are already direct [deps].

Public-API ignore-lists: already emptied (the entire ei_kwargs block was dropped in the prior commit). The three previously-ignored names are all recognized as public on the registered releases:

• AutoSpecialize → SciMLBase 3.27.0 (public)
• init, solve → CommonSolve 0.2.9 (public)

No names needed restoring.

Compat: bumped the qa-env floor SciMLTesting = "1.6" -> "1.7" so the resolved SciMLTesting always carries the >=1.11 gate for the two public-API checks (otherwise 1.6.x could resolve and spuriously flag public-backported names on the LTS). Root SciMLBase = "2.146, 3.1" already admits 3.27.0; CommonSolve = "0.2" admits 0.2.9.

Verification (registered releases, Pkg resolve, no dev of base libs):

• Julia 1.12 (public-API checks RUN, no ignores): QA group 18/18 pass, 0 fail/error/broken. Resolved SciMLBase 3.27.0, SciMLTesting 1.7.0, CommonSolve 0.2.9, ExplicitImports 1.15.0, JET 0.11.5, Aqua 0.8.16.
• Julia 1.10 lts (public-API checks skipped by the 1.7 gate): QA group 16/16 pass, 0 fail/error/broken. The 2-test delta vs 1.12 is exactly the two gated public-API checks.

qaFullyClean: no EI ignore-lists and no ei_broken/aqua_broken/jet_broken/@test_broken remain anywhere in src/ or test/. qa.jl collapses to run_qa(FiniteVolumeMethod1D; explicit_imports = true).

Rebased onto main (picked up Release v1.2.1 #98), Runic-clean, force-with-lease pushed.

Ignore until reviewed by @ChrisRackauckas.