Fold 48 issue-named workflow-markdown regression files into the canonical test
that owns each workflow aspect (execute-phase-*, plan-phase-*, quick-*, discuss-*,
worktree-cleanup, secure-phase, verify, update, settings, etc.), across 32 existing
suites. Verbatim block-scoped describe wrappers; 281 subtests conserved 1:1. No new
test files. Host-env pre-check: only gsd-settings-advanced spawns CLI and it sets no
GSD_WORKSTREAM/GSD_PROJECT value — no leak risk.
Regenerates regression-name allowlist (222->181), ratchets file-count allowlist
(verify 11->10), makes 30 relocated allow-test-rule exemptions issue-ref-compliant
(ADR-456; prunes 30 stale ids). lint:ci green.
Part of epic #1969. Closes#1973.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adds an opt-in --next (alias --rc) flag to /gsd-update targeting the @next RC dist-tag (ADR #660), with a {latest,next} allowlist enforced at three layers, channel-aware version check + banner, and byte-for-byte unchanged default @latest behavior.
Closes#815
