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/api/genlockes.ts

@@ -8,3 +8,7 @@ export function createGenlocke(data: CreateGenlockeInput): Promise<Genlocke> {
 export function getGamesByRegion(): Promise<Region[]> {
   return api.get('/games/by-region')
 }
+
+export function advanceLeg(genlockeId: number, legOrder: number): Promise<Genlocke> {
+  return api.post(`/genlockes/${genlockeId}/legs/${legOrder}/advance`, {})
+}