Add genlocke creation wizard with backend API and 4-step frontend

Implements the genlocke creation feature end-to-end: Genlocke and
GenlockeLeg models with migration, POST /genlockes endpoint that
creates the genlocke with all legs and auto-starts the first run,
and a 4-step wizard UI (Name, Select Games with preset templates,
Rules, Confirm) at /genlockes/new.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/hooks/useGenlockes.ts

@@ -0,0 +1,20 @@
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { createGenlocke, getGamesByRegion } from '../api/genlockes'
+import type { CreateGenlockeInput } from '../types/game'
+
+export function useRegions() {
+  return useQuery({
+    queryKey: ['games', 'by-region'],
+    queryFn: getGamesByRegion,
+  })
+}
+
+export function useCreateGenlocke() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (data: CreateGenlockeInput) => createGenlocke(data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['runs'] })
+    },
+  })
+}