Update project config for Go tool and port change

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>

.gitignore

@@ -60,5 +60,11 @@ temp/
 *.tmp
 *.temp
 
+# PokeAPI fetch cache
+.pokeapi_cache/
+
+# Go build output
+tools/fetch-pokeapi/fetch-pokeapi
+
 # Local config overrides
 *.local