fix(render+admin): render queue shows ALL users' jobs

The admin render queue called the user-scoped /v1/renders (so it only showed the
admin's own jobs) and parsed items/total instead of data/meta (→ always empty).
- render-svc: GET /v1/admin-renders (admin) → ListAllJobs across users, optional
  ?status= filter; gateway-wired
- admin renders page now fetches /v1/admin-renders and reads data/meta correctly

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/gateway/cmd/server/main.go

@@ -137,6 +137,7 @@ func main() {
 	v1.Any("/nodes/*path",        apiRL,   auth, render.Handler())
 	v1.Any("/node-fonts/*path",   apiRL,   auth, render.Handler())
 	v1.Any("/admin-exports/*path", apiRL,  auth, render.Handler())
+	v1.Any("/admin-renders",      apiRL,   auth, render.Handler())
 	v1.Any("/node-updates/*path", apiRL,   auth, render.Handler())
 
 	// ── Notification Service ──────────────────────────────────────────────────