[gouyt13]

Summary

PR #148 ran full validation both before and after merge because its lint-helper change fell outside the tagged-main routing-only exception. Reuse ordinary path classification for companion files: on tagged-version main, routing changes plus Python-quality/ShellCheck-only inputs retain those lightweight checks without repeating platform builds. Source, build, wheel-related and unknown inputs remain broad; PR routing validation and release safeguards are unchanged.

Add stable Clang validation and Core and FastScan validation summary jobs. They accept successful matrices or intentional skips confirmed by successful change detection; failures, cancellations and unexpected skips fail. This provides stable names for branch protection without requiring individual matrix names.

After these checks have run successfully on GitHub, register the two summary names as required checks. This PR does not perform that remote configuration change. Separate agent workflow templates and unrelated benchmark-coverage audit findings are excluded.

Testing

• New tagged-main combination regressions failed on the original classifier and pass with the fix; replaying PR ci: refine support-file triggers and lint coverage #148 selects Python quality plus ShellCheck on main and full checks on the PR.
• 26 helper tests and 222 subtests passed, including 120 state combinations executing the actual summary-job shell commands.
• Python lint/format, ShellCheck of extracted summary commands, YAML dependency checks, strict MkDocs build and diff checks passed.
• The main-deduplication change received two independent local reviews with no blocking findings. Summary jobs were added afterward and have local test coverage; cloud matrix behavior remains to be validated by this PR.

No local full-platform builds were run. actionlint was unavailable; YAML syntax and command wiring were checked locally. MkDocs emitted its existing Material advisory about MkDocs 2.0. This PR intentionally still runs full CI because it changes the classifier.