Retire the orchestrator's hardcoded ~28-token signal catalog by compiling a
routing index from article front-matter. New tools/Build-RoutingIndex.ps1 scans
all knowledge layers and emits routing-index.json (signal-token -> domain +
backing articles), seeded from the migrated legacy catalog (routing-seed.json)
so recall is never below today. Optional per-article 'signals:' front-matter
(validator rule R24) is the authored precision path; domain-normalization
reconciles front-matter/orchestrator/feedback domain vocabularies.
Artifact is a runtime build (gitignored), orchestrator-facing only (not the
lean agent-replayed knowledge index). CI guard Test-RoutingIndex.ps1 asserts
determinism, seed recall floor, no orphaned signals, and normalization
completeness; wired into the index workflow.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
