test(#1971): consolidate 48 gsd-tools CLI regression tests into subcommand suites

Fold 48 issue-named gsd-tools CLI regression files into the canonical test file
that owns each subcommand subject (state, roadmap, phase, milestone, audit, config,
router/dispatch, stats, verify, health, etc.), preserving every assertion and its
origin issue number as provenance (block-scoped describe wrappers, 299 subtests
conserved 1:1). No monolithic gsd-tools.test.cjs created — routes into 18 existing
per-subject suites.

Removes 48 tests/ files. Regenerates regression-name allowlist (271->231), ratchets
the file-count allowlist across 6 buckets (audit/milestone/phase/roadmap/state/verify),
and makes 10 relocated allow-test-rule exemptions issue-ref-compliant (ADR-456; prunes
10 stale ids). Repoints one CONTEXT.md symptom ref and ADR-3524's parity-test ref.
lint:ci green.

Part of epic #1969. Closes #1971.

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

CONTEXT.md

@@ -931,7 +931,7 @@ Full detail in `~/.claude/skills/gsd-pr-fix-discipline/SKILL.md`. AI agents MUST
 
 ### Slash command two-tier confusion
 
-- **Symptom:** `tests/bug-2543-gsd-slash-namespace.test.cjs` or `tests/bug-3584-runtime-slash-emitters.test.cjs` fails
+- **Symptom:** `tests/bug-2543-gsd-slash-namespace.test.cjs` or `tests/init-manager.test.cjs` (folds former `bug-3584-runtime-slash-emitters`, consolidation epic #1969) fails
 - **Affected this session:** #154 (three passes), #164 (added the authoritative matrix)
 - **Fix:** Consult `## Slash-command form` section of this file before touching any `/gsd-` or `/gsd:` token — colon for `agents/`/`commands/`, hyphen for runtime emitters