feat: refactor 30+ skills to Anthropic progressive disclosure pattern

- All SKILL.md files now <500 lines (avg reduction 69%)
- Detailed content extracted to references/ subdirectories
- Frontmatter standardised: only name + description (Anthropic standard)
- New skills: brand-guidelines, spec-coauthor, report-templates, skill-creator
- Design skills: anti-slop guidelines, premium-proposals reference
- Removed non-standard frontmatter fields (triggers, version, author, category)

Plugins affected: infraestrutura, marketing, dev-tools, crm-ops, gestao,
core-tools, negocio, perfex-dev, wordpress, design-media

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dev-tools/skills/db-design/SKILL.md

@@ -1,13 +1,6 @@
 ---
 name: db-design
-description: Database schema design and optimization. Creates normalized schemas,
-  indexes, and migration plans. Use when user mentions "database design", "schema",
-  "modelo dados", "database optimization", "sql design".
-author: Descomplicar® Crescimento Digital
-version: 1.0.0
-quality_score: 75
-user_invocable: true
-desk_task: 1469
+description: Design e optimização de schemas de base de dados — normalização, índices, planos de migração e particionamento.
 ---
 
 # Database Design Specialist