remove the desktop-pet system

The pet feature was three loosely coupled subsystems that no core flow
depended on: the Petdex catalog page, the pet install/preference store, and
the pet-state socket. All three are removed.

The only cross-boundary touch point was a try/catch-wrapped observer that
mapped chat-run events to pet animations. Removing it leaves the /chat-run
event contract unchanged: no event name, field name, field type, or emission
timing changed.

Removing petdexPublicRoutes also closes the unauthenticated outbound proxy
at /api/hermes/petdex/asset, which shrinks the SSRF surface.

packages/client/src/router/index.ts

@@ -109,11 +109,6 @@ const router = createRouter({
       name: 'hermes.plugins',
       component: () => import('@/views/hermes/PluginsView.vue'),
     },
-    {
-      path: '/hermes/petdex',
-      name: 'hermes.petdex',
-      component: () => import('@/views/hermes/PetdexView.vue'),
-    },
     {
       path: '/hermes/memory',
       name: 'hermes.memory',