test(#1975): consolidate 51 CLI + scripts-tooling regression tests into module suites

Fold 51 issue-named CLI black-box + scripts-tooling regression files into their
canonical module suites (runtime-launcher-parity, worktree-safety, install-*, managed-hooks,
read-guard, capability-registry, etc.), plus a NEW slash-command-namespace.test.cjs grouping
the 4 slash/colon-namespace-leak invariant suites that had no canonical owner. Verbatim
block-scoped describe wrappers; 427 subtests conserved 1:1.

Host-env pre-check (per B2): no CLI-receiving host sets a redirecting GSD_WORKSTREAM/GSD_PROJECT
value. One folded suite (bug-3668 runtime resolver) creates an extension-less PATH gsd-tools
stub + bash -c; co-locating it with the host's chmodSync tripped local/no-unguarded-nonportable-exec,
so it's now Windows-guarded (skip on win32) matching the host suite's own bash -c guard.

Regenerates regression-name allowlist (222->182), ratchets file-count allowlist (graphify 7->6,
docs entry removed), makes 26 relocated allow-test-rule exemptions issue-ref-compliant (ADR-456;
prunes stale ids). Repoints 13 tests/ references across CONTEXT.md, COMMANDS.md/FEATURES.md
(EN + ja/ko/pt/zh) and ADR-0002. lint:ci green.

Part of epic #1969. Closes #1975.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/adr/0002-command-contract-validation-module.md

@@ -18,7 +18,7 @@ The command file contract defines what makes a valid `commands/gsd/*.md`:
 ## Context
 
 Before this ADR, the command contract was enforced inconsistently:
-- `tests/enh-2790-skill-consolidation.test.cjs` checked existence and frontmatter of specific post-consolidation commands
+- `tests/skill-frontmatter-contract.test.cjs` (folds former `enh-2790-skill-consolidation`, consolidation epic #1969) checked existence and frontmatter of specific post-consolidation commands
 - `tests/docs-update.test.cjs` (folds former `bug-3135-capture-backlog-workflow`, consolidation epic #1969) checked `execution_context` @-ref resolution (added 2026-05-05)
 - No test checked `allowed-tools` validity, `name:` convention, or `description:` non-emptiness across all commands simultaneously