docs: Add categories to-do list for future expansion

Tracks potential Kiwix categories to add to the tiered collections
system, organized by priority level.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

collections/CATEGORIES-TODO.md

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+# Kiwix Categories To-Do List
+
+Potential categories to add to the tiered collections system in `kiwix-categories.json`.
+
+## Current Categories (Completed)
+- [x] Medicine - Medical references, first aid, emergency care
+- [x] Survival & Preparedness - Food prep, prepper videos, repair guides
+- [x] Education & Reference - Wikipedia, textbooks, TED talks
+
+---
+
+## High Priority
+
+### Technology & Programming
+Stack Overflow, developer documentation, coding tutorials
+- Stack Overflow (multiple tags available)
+- DevDocs documentation
+- freeCodeCamp
+- Programming language references
+
+### Children & Family
+Age-appropriate educational content for kids
+- Wikipedia for Schools
+- Wikibooks Children's Bookshelf
+- Khan Academy Kids (via Kolibri - separate system)
+- Storybooks, fairy tales
+
+### Trades & Vocational
+Practical skills for building, fixing, and maintaining
+- Electrical wiring guides
+- Plumbing basics
+- Automotive repair
+- Woodworking
+- Welding fundamentals
+
+### Agriculture & Gardening
+Food production and farming (expand beyond what's in Survival)
+- Practical Plants database
+- Permaculture guides
+- Seed saving
+- Animal husbandry
+- Composting and soil management
+
+---
+
+## Medium Priority
+
+### Languages & Reference
+Dictionaries, language learning, translation
+- Wiktionary (multiple languages)
+- Language learning resources
+- Translation dictionaries
+- Grammar guides
+
+### History & Culture
+Historical knowledge and cultural encyclopedias
+- Wikipedia History portal content
+- Historical documents
+- Cultural archives
+- Biographies
+
+### Legal & Civic
+Laws, rights, and civic procedures
+- Legal references
+- Constitutional documents
+- Civic procedures
+- Rights and responsibilities
+
+### Communications
+Emergency and amateur radio, networking
+- Ham radio guides
+- Emergency communication protocols
+- Basic networking/IT
+- Signal procedures
+
+---
+
+## Nice To Have
+
+### Entertainment
+Recreational reading and activities
+- Project Gutenberg (fiction categories)
+- Chess tutorials
+- Puzzles and games
+- Music theory
+
+### Religion & Philosophy
+Spiritual and philosophical texts
+- Religious texts (various traditions)
+- Philosophy references
+- Ethics guides
+
+### Regional/Non-English Bundles
+Content in other languages
+- Spanish language bundle
+- French language bundle
+- Other major languages
+
+---
+
+## Notes
+
+- Each category should have 3 tiers: Essential, Standard, Comprehensive
+- Higher tiers include all content from lower tiers via `includesTier`
+- Check Kiwix catalog for available ZIM files: https://download.kiwix.org/zim/
+- Consider storage constraints - Essential tiers should be <500MB ideally
+- Mark one tier as `recommended: true` (usually Essential)