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/common-mistakes.md

@@ -0,0 +1,10 @@
+# Common Mistakes
+
+1. **Using AI for product UI screenshots** — models hallucinate interfaces; capture real screenshots
+2. **Skipping image optimization** — unoptimized images are the #1 page speed killer
+3. **No OG image** — shared links look broken without a preview image
+4. **Wrong aspect ratio** — always check platform specs before generating
+5. **Text-heavy images without Ideogram** — most AI models butcher text; use Ideogram or add text in post
+6. **Generating without style direction** — "photorealistic," "flat illustration," "3D render" drastically changes output
+7. **Inconsistent brand visuals** — use Flux multi-reference or design templates for consistency
+8. **Huge images on landing pages** — compress, resize, lazy load