Document exported strategy kind constants

[ChrisRackauckas-Claude]

Summary

Ignore this PR until reviewed by @ChrisRackauckas.

This PR completes public API documentation coverage for the exported StrategyKind enum values by:

• adding per-constant source docs immediately after the @enum definition in src/kinds.jl
• adding the exported KIND_* constants to the rendered docs via a @docs block in docs/src/strategies.md
• adding a QA guard that checks every exported FindFirstFunctions-owned public name has real Base.Docs metadata and appears in a docs @docs block

The per-constant docs use detached @doc only because Julia 1.10's @enum rejects inline docstrings for individual enum values.

Validation

• git diff --check
• timeout 3600 /home/crackauc/.juliaup/bin/julia +1.10 --project=. --startup-file=no -e 'using Runic; Runic.main(["--check", "src/kinds.jl", "test/qa/qa.jl", "docs/src/strategies.md"])'
• focused public-doc audit: missing source docs: Symbol[], missing rendered docs: Symbol[]
• timeout 3600 /home/crackauc/.juliaup/bin/julia +1.10 --project=. --startup-file=no -e 'using Pkg; Pkg.test()' passed: Core/core_tests.jl | 105036 105036
• timeout 3600 /home/crackauc/.juliaup/bin/julia +1.10 --project=. --startup-file=no -e 'using Pkg; ENV["GROUP"] = "QA"; Pkg.test()' passed: QA/qa.jl | 18 18, QA/static_analysis_tests.jl | 34 34

Docs build note: the official local docs command failed on linkcheck with HTTP 429 for https://github.com/SciML/FindFirstFunctions.jl/blob/main/bench/analyze.jl. I reproduced the same failure from origin/main in an extracted clean copy, so it is not introduced by this branch. The GitHub Documentation check for this PR passed.

Remote CI note: the benchmark / Benchmarks check failed because AirspeedVelocity's temporary benchmark environment cannot load StableRNGs from benchmark/benchmarks.jl. The same Package StableRNGs not found in current path failure appears in prior benchmark run 29074814177, so this is a pre-existing benchmark workflow dependency issue rather than a regression from this docs PR.