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>

design-review/SKILL.md

@@ -997,6 +997,7 @@ 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 "Review the frontend source code in this repo. Evaluate against these design hard rules:
 - Spacing: systematic (design tokens / CSS variables) or magic numbers?
 - Typography: expressive purposeful fonts or default stacks?
@@ -1026,7 +1027,7 @@ HARD REJECTION — flag if ANY apply:
 6. Carousel with no narrative purpose
 7. App UI made of stacked cards instead of layout
 
-Be specific. Reference file:line for every finding." -C "$(git rev-parse --show-toplevel)" -s read-only -c 'model_reasoning_effort="high"' --enable web_search_cached 2>"$TMPERR_DESIGN"
+Be specific. Reference file:line for every finding." -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