refactor(runtime): rename extras/ to runtime/, drop obsolete modrinth list

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -1,7 +1,7 @@
 .env
 backups/
 drasl/config/keycloak-client-secret
-extras/authlib-injector.jar
+runtime/authlib-injector.jar
 
 # rendered configs (from tooling/render-config.sh)
 drasl/config/config.toml