feat: always-on adversarial review + scope drift + plan mode design tools (v0.14.3.0) (#694)

* feat: always-on adversarial review + scope drift resolver + cross-model tension format

Rewrite generateAdversarialStep() to remove LOC-based tier skipping. Every review
now runs both Claude adversarial subagent and Codex adversarial challenge. OLD_CFG
only gates Codex passes, not Claude. Add generateScopeDrift() shared resolver.
Fix cross-model tension AskUserQuestion to include RECOMMENDATION + Completeness.

* feat: add scope drift to /ship, extract from /review template

/ship gets {{SCOPE_DRIFT}} at Step 3.48 + PR body slot. /review replaces
hardcoded scope drift with {{SCOPE_DRIFT}} + {{PLAN_COMPLETION_AUDIT_REVIEW}}.

* feat: plan mode safe operations — browse, design, codex allowed in plan mode

Add preamble section declaring $B, $D, codex, and ~/.gstack/ writes as
plan-mode-safe. Unblocks design skills during planning.

* test: update adversarial + add scope drift assertions

Rename adversarial tests to reflect always-on behavior. Remove tier
threshold assertions. Add scope drift content assertions for both
/review and /ship generated SKILL.md files.

* chore: bump version and changelog (v0.14.3.0)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

plan-eng-review/SKILL.md

@@ -375,6 +375,21 @@ If you cannot determine the outcome, use "unknown". Both local JSONL and remote
 telemetry only run if telemetry is not off. The remote binary additionally requires
 the binary to exist.
 
+## Plan Mode Safe Operations
+
+When in plan mode, these operations are always allowed because they produce
+artifacts that inform the plan, not code changes:
+
+- `$B` commands (browse: screenshots, page inspection, navigation, snapshots)
+- `$D` commands (design: generate mockups, variants, comparison boards, iterate)
+- `codex exec` / `codex review` (outside voice, plan review, adversarial challenge)
+- Writing to `~/.gstack/` (config, analytics, review logs, design artifacts, learnings)
+- Writing to the plan file (already allowed by plan mode)
+- `open` commands for viewing generated artifacts (comparison boards, HTML previews)
+
+These are read-only in spirit — they inspect the live site, generate visual artifacts,
+or get independent opinions. They do NOT modify project source files.
+
 ## Plan Status Footer
 
 When you are in plan mode and about to call ExitPlanMode:
@@ -963,6 +978,9 @@ For each substantive tension point, use AskUserQuestion:
 
 > "Cross-model disagreement on [topic]. The review found [X] but the outside voice
 > argues [Y]. [One sentence on what context you might be missing.]"
+>
+> RECOMMENDATION: Choose [A or B] because [one-line reason explaining which argument
+> is more compelling and why]. Completeness: A=X/10, B=Y/10.
 
 Options:
 - A) Accept the outside voice's recommendation (I'll apply this change)
@@ -1149,7 +1167,7 @@ Display:
 - **Eng Review (required by default):** The only review that gates shipping. Covers architecture, code quality, tests, performance. Can be disabled globally with \`gstack-config set skip_eng_review true\` (the "don't bother me" setting).
 - **CEO Review (optional):** Use your judgment. Recommend it for big product/business changes, new user-facing features, or scope decisions. Skip for bug fixes, refactors, infra, and cleanup.
 - **Design Review (optional):** Use your judgment. Recommend it for UI/UX changes. Skip for backend-only, infra, or prompt-only changes.
-- **Adversarial Review (automatic):** Auto-scales by diff size. Small diffs (<50 lines) skip adversarial. Medium diffs (50–199) get cross-model adversarial. Large diffs (200+) get all 4 passes: Claude structured, Codex structured, Claude adversarial subagent, Codex adversarial. No configuration needed.
+- **Adversarial Review (automatic):** Always-on for every review. Every diff gets both Claude adversarial subagent and Codex adversarial challenge. Large diffs (200+ lines) additionally get Codex structured review with P1 gate. No configuration needed.
 - **Outside Voice (optional):** Independent plan review from a different AI model. Offered after all review sections complete in /plan-ceo-review and /plan-eng-review. Falls back to Claude subagent if Codex is unavailable. Never gates shipping.
 
 **Verdict logic:**