- New parser (contentPlanParser.js): splits text by "Письмо N.", extracts subject/preheader, recognizes text/products/buttons/banners/headings
- Supports all 3 project formats: AT, numizmatRU, KB (different ID formats, markers)
- New mapper (contentPlanMapper.js): converts parsed blocks to Pug block structures
- UI modal: paste text → preview parsed letters → create all at once
- Auto-matches subjects to plan rows for dates
- Product IDs auto-split into blocks of 1-3 based on available mixins