feat(portal): strip Vuexy demo content and create clean portal shell

Remove all demo pages, dialogs, sidebar navigation, and layout components.
Create minimal top-bar portal layout with auth-aware navigation, placeholder
pages for volunteer registration, dashboard, shifts, profile, artist advance,
and login. Add Pinia auth store, axios with Sanctum support, and router guards.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/portal/themeConfig.ts

@@ -10,7 +10,7 @@ import { AppContentLayoutNav, ContentWidth, FooterType, NavbarType } from '@layo
 
 export const { themeConfig, layoutConfig } = defineThemeConfig({
   app: {
-    title: 'Portal',
+    title: 'Crewli Portal',
     logo: h('div', { innerHTML: logo, style: 'line-height:0; color: rgb(var(--v-global-theme-primary))' }),
     contentWidth: ContentWidth.Boxed,
     contentLayoutNav: AppContentLayoutNav.Vertical,
@@ -36,7 +36,7 @@ export const { themeConfig, layoutConfig } = defineThemeConfig({
         },
       ],
     },
-    theme: 'system',
+    theme: 'light',
     skin: Skins.Default,
     iconRenderer: VIcon,
   },