feat: cross-model outside voice in plan reviews (v0.9.9.1) (#326)

* feat: add generateCodexPlanReview() resolver for cross-model plan review

New resolver offers an optional Codex (or Claude subagent fallback) "outside
voice" after plan review sections complete. Includes cross-model tension
detection with auto-TODO proposals, review log persistence, and an Outside
Voice row in the Review Readiness Dashboard.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: integrate {{CODEX_PLAN_REVIEW}} into CEO and eng review templates

CEO review: insert after Section 11 + add Outside Voice summary row.
Eng review: replace hardcoded Step 0.5 with resolver (adds fallback,
logging, dashboard, xhigh reasoning, cross-model tension tracking).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate SKILL.md files from updated templates

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: update project documentation for v0.9.9.1

ARCHITECTURE.md: added {{CODEX_PLAN_REVIEW}} to placeholder table.
CHANGELOG.md: added v0.9.9.1 entry for outside voice feature.
VERSION: bumped to 0.9.9.1.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: move {{CODEX_PLAN_REVIEW}} after review sections in eng review

Codex adversarial review caught that the placeholder was positioned
before the 4 review sections, so the "After all review sections are
complete" instruction could confuse the model. Moved it after Section
4's STOP directive where it belongs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate eng review SKILL.md files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ship/SKILL.md

@@ -356,7 +356,7 @@ After completing the review, read the review log and config to display the dashb
 ~/.claude/skills/gstack/bin/gstack-review-read
 ```
 
-Parse the output. Find the most recent entry for each skill (plan-ceo-review, plan-eng-review, plan-design-review, design-review-lite, adversarial-review, codex-review). Ignore entries with timestamps older than 7 days. For the Adversarial row, show whichever is more recent between `adversarial-review` (new auto-scaled) and `codex-review` (legacy). For Design Review, show whichever is more recent between `plan-design-review` (full visual audit) and `design-review-lite` (code-level check). Append "(FULL)" or "(LITE)" to the status to distinguish. Display:
+Parse the output. Find the most recent entry for each skill (plan-ceo-review, plan-eng-review, plan-design-review, design-review-lite, adversarial-review, codex-review, codex-plan-review). Ignore entries with timestamps older than 7 days. For the Adversarial row, show whichever is more recent between `adversarial-review` (new auto-scaled) and `codex-review` (legacy). For Design Review, show whichever is more recent between `plan-design-review` (full visual audit) and `design-review-lite` (code-level check). Append "(FULL)" or "(LITE)" to the status to distinguish. Display:
 
 ```
 +====================================================================+
@@ -368,6 +368,7 @@ Parse the output. Find the most recent entry for each skill (plan-ceo-review, pl
 | CEO Review      |  0   | —                   | —         | no       |
 | Design Review   |  0   | —                   | —         | no       |
 | Adversarial     |  0   | —                   | —         | no       |
+| Outside Voice   |  0   | —                   | —         | no       |
 +--------------------------------------------------------------------+
 | VERDICT: CLEARED — Eng Review passed                                |
 +====================================================================+
@@ -378,6 +379,7 @@ Parse the output. Find the most recent entry for each skill (plan-ceo-review, pl
 - **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.
+- **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:**
 - **CLEARED**: Eng Review has >= 1 entry within 7 days with status "clean" (or \`skip_eng_review\` is \`true\`)