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>

automacao/skills/n8n-sync/SKILL.md

@@ -1,3 +1,9 @@
+---
+name: n8n-sync
+description: Sincronização de dados entre sistemas via workflows n8n. Mantém dados consistentes entre plataformas.
+disable-model-invocation: true
+---
+
 # /n8n-sync - Sincronização de Dados n8n
 
 Manter dados sincronizados entre sistemas.