fix: extend tilde-in-assignment fix to design resolver + 4 skill templates

PR #993 fixed the Claude Code permission prompt for `scripts/resolvers/browse.ts`
and `gstack-upgrade/SKILL.md.tmpl`. Same bug lives in three more places that
weren't on the contributor's branch:

- `scripts/resolvers/design.ts` (3 spots: D=, B=, and _DESIGN_DIR=)
- `design-shotgun/SKILL.md.tmpl` (_DESIGN_DIR=)
- `plan-design-review/SKILL.md.tmpl` (_DESIGN_DIR=)
- `design-consultation/SKILL.md.tmpl` (_DESIGN_DIR=)
- `design-review/SKILL.md.tmpl` (REPORT_DIR=)

Replaces bare `~/` with quoted `"$HOME/..."` in the source-of-truth files, then
regenerates. `grep -rEn '^[A-Za-z_]+=~/' --include="SKILL.md" .` now returns zero
hits across all hosts (claude, codex, cursor, gbrain, hermes).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

office-hours/SKILL.md

@@ -1124,7 +1124,7 @@ Present via AskUserQuestion. Do NOT proceed without user approval of the approac
 _ROOT=$(git rev-parse --show-toplevel 2>/dev/null)
 D=""
 [ -n "$_ROOT" ] && [ -x "$_ROOT/.claude/skills/gstack/design/dist/design" ] && D="$_ROOT/.claude/skills/gstack/design/dist/design"
-[ -z "$D" ] && D=~/.claude/skills/gstack/design/dist/design
+[ -z "$D" ] && D="$HOME/.claude/skills/gstack/design/dist/design"
 [ -x "$D" ] && echo "DESIGN_READY" || echo "DESIGN_NOT_AVAILABLE"
 ```
 
@@ -1139,7 +1139,7 @@ Generating visual mockups of the proposed design... (say "skip" if you don't nee
 
 ```bash
 eval "$(~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null)"
-_DESIGN_DIR=~/.gstack/projects/$SLUG/designs/mockup-$(date +%Y%m%d)
+_DESIGN_DIR="$HOME/.gstack/projects/$SLUG/designs/mockup-$(date +%Y%m%d)"
 mkdir -p "$_DESIGN_DIR"
 echo "DESIGN_DIR: $_DESIGN_DIR"
 ```