feat: /design-consultation — risk-taking thesis, visual research, ambitious preview

Add SAFE/RISK breakdown to design proposals so users see which choices
match category conventions vs. which are deliberate creative departures.

Wire browse binary for visual competitive research — agent browses
competitor sites, takes screenshots, and analyzes fonts/colors/spacing
with graceful degradation to WebSearch-only or built-in knowledge.

Upgrade preview page instructions to render realistic product mockups
(dashboards, marketing pages, settings forms) instead of just swatches.

Rewrite README section with the thesis: "coherence is table stakes —
the real question is where you take risks."

qa-design-review/SKILL.md.tmpl

@@ -191,7 +191,7 @@ Write the report to both local and project-scoped locations:
 
 **Project-scoped:**
 ```bash
-SLUG=$(git remote get-url origin 2>/dev/null | sed 's|.*[:/]\([^/]*/[^/]*\)\.git$|\1|;s|.*[:/]\([^/]*/[^/]*\)$|\1|' | tr '/' '-')
+eval $(~/.claude/skills/gstack/bin/gstack-slug 2>/dev/null)
 mkdir -p ~/.gstack/projects/$SLUG
 ```
 Write to `~/.gstack/projects/{slug}/{user}-{branch}-design-audit-{datetime}.md`