Add genlocke leg progression with advance endpoint and run context

When a run belonging to a genlocke is completed or failed, the genlocke
status updates accordingly. The run detail API now includes genlocke
context (leg order, total legs, genlocke name). A new advance endpoint
creates the next leg's run, and the frontend shows genlocke-aware UI
including a "Leg X of Y" banner, advance button, and contextual
messaging in the end-run modal.

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

frontend/src/hooks/useGenlockes.ts

@@ -1,5 +1,5 @@
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
-import { createGenlocke, getGamesByRegion } from '../api/genlockes'
+import { advanceLeg, createGenlocke, getGamesByRegion } from '../api/genlockes'
 import type { CreateGenlockeInput } from '../types/game'
 
 export function useRegions() {
@@ -18,3 +18,14 @@ export function useCreateGenlocke() {
     },
   })
 }
+
+export function useAdvanceLeg() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: ({ genlockeId, legOrder }: { genlockeId: number; legOrder: number }) =>
+      advanceLeg(genlockeId, legOrder),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['runs'] })
+    },
+  })
+}