Spec Kitty

Mission Run: Decide the fate of out-of-matrix test directories

Turn the recorded out-of-matrix test-directory inventory from a passive snapshot into deliberate, evidence-backed CI coverage decisions so no test tree is silently unrun on main.

Issue #4369 made every un-lane'd test directory visible in the CI module registry but explicitly deferred deciding what to do about them. This mission closes that decision debt: for each secondary test tree, it either promotes the tree into a CI lane (backed by a measured timing run) or records a sharpened reason explaining why an existing gate already covers it. The outcome is a registry whose out-of-matrix entries are decisions, not snapshots, protecting the project from regressions that would otherwise persist unseen on the main branch.