refactor(skills): move image catalogs to references

Keep the decision steps in SKILL.md and move catalogs, examples, and
checklists verbatim to references/ to reduce the context cost of loading the
skill.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shared/skills/image/references/design-tools.md

@@ -0,0 +1,32 @@
+# Design Tools
+
+For templated, brand-consistent work where AI generation is overkill or too unpredictable.
+
+## Canva
+
+Best for non-designers who need polished output fast.
+
+- **Strengths:** Massive template library, brand kit, Magic Resize (one design → all sizes), team collaboration
+- **Best for:** Social graphics, presentations, email headers, simple banners
+- **Limitations:** Less control than Figma, templates can look generic
+- **Agent-friendliness:** Has an API but limited — better as a human-in-the-loop tool
+
+## Figma
+
+Best for teams with design systems or pixel-perfect needs.
+
+- **Strengths:** Design system components, auto layout, developer handoff, plugins
+- **Best for:** OG images via templates, design system assets, complex layouts
+- **Limitations:** Steeper learning curve, requires design skill
+- **Agent-friendliness:** Has an API and MCP server for reading designs
+
+## When to Use Design Tools vs. AI Generation
+
+| Scenario | Design Tool | AI Generation |
+|----------|:-:|:-:|
+| Exact brand guidelines must be followed | Yes | Maybe (with strong ref images) |
+| Need 20 size variants of one design | Yes (Canva Magic Resize) | No |
+| Unique hero image for a blog post | No | Yes |
+| Recurring social media template | Yes | No |
+| Product mockup with real UI | No (use screenshots) | No (hallucinated UI) |
+| Abstract/creative visual | No | Yes |