Add mappings module with pokemon form, location area, encounter method,
and version mappings. Auto-download PokeDB JSON exports from CDN on
first run, caching in .pokedb_cache/.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add Go to .tool-versions, update .gitignore for Go build output and
cache, document seed data regeneration in README, and change API port
from 8000 to 8080 in docker-compose.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>