fix: resolve codex exec -C repo root eagerly to prevent wrong-project reviews

When codex exec commands run in background bash tasks (e.g., Conductor
workspaces), $(git rev-parse --show-toplevel) evaluates in whatever cwd
the background shell inherits, which may be a different project. Fix by
resolving _REPO_ROOT once at the top of each bash block and referencing
the stored value in -C.

12 occurrences fixed across 4 source files:
- codex/SKILL.md.tmpl (3)
- autoplan/SKILL.md.tmpl (3)
- scripts/resolvers/review.ts (3)
- scripts/resolvers/design.ts (3)

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

plan-design-review/SKILL.md

@@ -489,6 +489,7 @@ which codex 2>/dev/null && echo "CODEX_AVAILABLE" || echo "CODEX_NOT_AVAILABLE"
 1. **Codex design voice** (via Bash):
 ```bash
 TMPERR_DESIGN=$(mktemp /tmp/codex-design-XXXXXXXX)
+_REPO_ROOT=$(git rev-parse --show-toplevel 2>/dev/null || pwd)
 codex exec "Read the plan file at [plan-file-path]. Evaluate this plan's UI/UX design against these criteria.
 
 HARD REJECTION — flag if ANY apply:
@@ -514,7 +515,7 @@ HARD RULES — first classify as MARKETING/LANDING PAGE vs APP UI vs HYBRID, the
 - APP UI: Calm surface hierarchy, dense but readable, utility language, minimal chrome
 - UNIVERSAL: CSS variables for colors, no default font stacks, one job per section, cards earn existence
 
-For each finding: what's wrong, what will happen if it ships unresolved, and the specific fix. Be opinionated. No hedging." -C "$(git rev-parse --show-toplevel)" -s read-only -c 'model_reasoning_effort="high"' --enable web_search_cached 2>"$TMPERR_DESIGN"
+For each finding: what's wrong, what will happen if it ships unresolved, and the specific fix. Be opinionated. No hedging." -C "$_REPO_ROOT" -s read-only -c 'model_reasoning_effort="high"' --enable web_search_cached 2>"$TMPERR_DESIGN"
 ```
 Use a 5-minute timeout (`timeout: 300000`). After the command completes, read stderr:
 ```bash