fix: add missing scope and config_snapshot fields to createCompetition

Backend requires scope and config_snapshot when creating competition
without a template. Frontend now:
- Defaults scope to 'facility' when facility_id is provided
- Renames config to config_snapshot for backend compatibility
- Provides empty config_snapshot when no template_id

src/lib/api/competition-admin.ts

@@ -263,10 +263,26 @@ export async function createCompetition(
   request: CreateCompetitionRequest
 ): Promise<CompetitionApiResult<Competition>> {
   try {
+    // Build request body with proper field names for backend
+    const { config, ...rest } = request;
+    const body: Record<string, unknown> = {
+      ...rest,
+      facility_id: facilityId,
+      scope: request.scope ?? 'facility', // Default to facility scope
+    };
+
+    // Backend expects config_snapshot, not config
+    if (config) {
+      body.config_snapshot = config;
+    } else if (!request.template_id) {
+      // Provide empty config_snapshot when creating without template
+      body.config_snapshot = {};
+    }
+
     const response = await apiFetch('/competitions', {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ ...request, facility_id: facilityId }),
+      body: JSON.stringify(body),
     });
 
     const result = await handleApiResponse<{ competition: Competition }>(response);