Document ComplementaritySolve public API

[ChrisRackauckas-Claude]

Ignore until reviewed by @ChrisRackauckas.

Summary

• Adds SciMLStyle docstrings and rendered documentation for ComplementaritySolve-owned exported problem, algorithm, sensitivity, system, alias, and solution APIs.
• Pins the registered SciMLTesting test compat to exactly "2.4" without changing its UUID or adding a path/source override.
• Uses SciMLTesting 2.4 defaults for rendered-doc and explicit-import checks.
• Preserves the existing CommonSolve solve reexport with fixed reexports_allow = (:solve,) and excludes only that dependency-owned name from local rendered docs.
• Uses a normal definition-site docstring for LinearComplementaritySystem and removes the obsolete Markdown import and dependency; no public API changed.

Validation

• timeout 3600 env TESTING_GROUP=QA BACKEND_GROUP=CPU /home/crackauc/.juliaup/bin/julia +release --project=. -e "using Pkg; Pkg.resolve(); Pkg.test(; coverage=false)"
  • Registry test sandbox resolved SciMLTesting v2.4.0.
  • Complementarity Solve | 13 pass | 13 total | 1m06.6s; exit code 0.
• timeout 3600 /home/crackauc/.juliaup/bin/julia +release --project=. -e "using Pkg; Pkg.test(; coverage=false)"
  • Complementarity Solve | 266 pass | 7 broken | 273 total | 27m37.6s; exit code 0.
• timeout 3600 /home/crackauc/.juliaup/bin/julia +release --project=/home/crackauc/sandbox/tmp_20260708_051717_3275/.runic_env -m Runic --check src test docs/make.jl
  • Runic v1.7.0; exit code 0.
• git diff --check
• Source/PR audit found no remaining @doc, doc""", @doc_str, or Markdown source references.

No [sources], package path entries, absolute paths, temporary files, or generated manifests are included.