Phase 0: Replace Vuexy design system with custom EZSCALE foundation

- Install echarts, vue-echarts, @vueuse/core; remove @mdi/font
- Switch fonts from Inter/Public Sans to Plus Jakarta Sans/JetBrains Mono
- Delete all 38 @core SCSS files, replace with 6 new design token files
  (_variables, _mixins, _animations, _typography, _component-overrides, _layouts)
- Rewrite _marketing.scss with glass morphism and dark grid hero styles
- Update Vuetify theme from purple (#7367F0) to navy blue (#1d4ed8)
- Add pill-shaped buttons, tonal chips, rounded cards to Vuetify defaults
- Make default theme subdomain-aware (light for marketing, dark for app)
- Remove @core-scss and @configured-variables Vite aliases
- Fix AuthLayout and AppStepper to remove deleted @core SCSS imports

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

website/vite.config.ts

@@ -29,8 +29,6 @@ export default defineConfig({
       '@': fileURLToPath(new URL('./resources/ts', import.meta.url)),
       '@images': fileURLToPath(new URL('./resources/images/', import.meta.url)),
       '@styles': fileURLToPath(new URL('./resources/styles/', import.meta.url)),
-      '@core-scss': fileURLToPath(new URL('./resources/styles/@core', import.meta.url)),
-      '@configured-variables': fileURLToPath(new URL('./resources/styles/variables/_template.scss', import.meta.url)),
       '@layouts': fileURLToPath(new URL('./resources/ts/@layouts', import.meta.url)),
     },
   },