WebhookService parses YAML-fenced issue body, filters by "weapon-mod" label, deduplicates via Redis SETNX with 12h TTL, and delegates to ModificationManager for single/batch creation. GitHubWebhookController verifies X-GitHub-Event=issues and action=opened before delegating to the service. Register GitHubWebhookInterceptor for /webhooks/github in AppConfig.