Add a guided setup after signup, and a no-model notice in conversations

The first super admin now lands on Settings > Setup after signing up: a
skippable walk through the app name, connecting a model provider and
picking models, ending with where to go next. It stays under Settings to
come back to.

While a bot has no text model, its conversation shows a notice in the
thread (centred when empty): super admins get Connect a provider and
Guided setup, everyone else is told the super admin sets it up. The
models modal keeps it current.

The Models page's data and save logic move into useModelsOverview, shared
with the setup.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/dict/settings-pages-dict.ts

@@ -10,6 +10,7 @@ import {
     LockKeyhole,
     Monitor,
     Plug,
+    Rocket,
     Users,
     SlidersHorizontal,
     UserRound,
@@ -38,6 +39,8 @@ export type SettingsPage = {
 export const SettingsComputersPath = "/admin/settings/computers";
 export const SettingsBackupsPath = "/admin/settings/backups";
 export const SettingsDatabasePath = "/admin/settings/database";
+export const SettingsSetupPath = "/admin/settings/setup";
+export const SettingsModelsPath = "/admin/settings/models";
 
 /**
  * The `/admin/settings/*` sub pages, listed in the rail on every settings
@@ -49,6 +52,12 @@ export const SettingsPages: SettingsPage[] = [
         url: "/admin/settings/general",
         Icon: SlidersHorizontal,
     },
+    {
+        title: "Setup",
+        url: SettingsSetupPath,
+        Icon: Rocket,
+        super_admin_only: true,
+    },
     { title: "Profile", url: "/admin/settings/profile", Icon: UserRound },
     {
         title: "Change password",
@@ -71,7 +80,7 @@ export const SettingsPages: SettingsPage[] = [
     },
     {
         title: "Models",
-        url: "/admin/settings/models",
+        url: SettingsModelsPath,
         Icon: CpuAi,
         super_admin_only: true,
     },