feat: fold traefik into the service widget type, remove the dedicated one

Traefik gets the same treatment as the other six services now instead
of a bespoke widget type: docker health merged with a single "Routes"
stat, via the same internal container-to-container API call
(http://traefik:8080/api/http/routers) it already used. No auth
needed, same as before.

Deleted lib/collectors/traefik.ts, lib/types/traefik-result.ts, and
components/widgets/traefik/ entirely - the generic service Widget.tsx
and ServiceWidgetResult shape cover it with zero new component code.

lib/collectors/service.ts

@@ -7,6 +7,7 @@ import { collectImmich } from "./services/immich";
 import { collectN8n } from "./services/n8n";
 import { collectUmami } from "./services/umami";
 import { collectHeadscale } from "./services/headscale";
+import { collectTraefikStat } from "./services/traefik";
 
 function collectServiceStat(widget: ServiceWidget): Promise<{ stats: ServiceStat[]; detail?: string[] }> {
   switch (widget.service) {
@@ -22,6 +23,8 @@ function collectServiceStat(widget: ServiceWidget): Promise<{ stats: ServiceStat
       return collectUmami(widget);
     case "headscale":
       return collectHeadscale(widget);
+    case "traefik":
+      return collectTraefikStat(widget);
   }
 }