De-template the frontend and apply the design system

- FastAPI branding replaced throughout: title, favicon, logo (now the org/
  brand SVGs), footer links, route titles; workspace package renamed
- shadcn primitives restyled to the component radius/shadow map: pill
  controls, rounded-lg surfaces, shadow-e1/e2/e3
- floating frosted AppSidebar over a bg-card content region
- theme storage key aligned with the pre-paint script, MotionConfig added
- scripts/capture-screenshots.mjs backs the root 'make verify'

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/routeTree.gen.ts

@@ -65,6 +65,7 @@ const LayoutAdminRoute = LayoutAdminRouteImport.update({
 } as any)
 
 export interface FileRoutesByFullPath {
+  '/': typeof LayoutIndexRoute
   '/login': typeof LoginRoute
   '/recover-password': typeof RecoverPasswordRoute
   '/reset-password': typeof ResetPasswordRoute
@@ -72,7 +73,6 @@ export interface FileRoutesByFullPath {
   '/admin': typeof LayoutAdminRoute
   '/items': typeof LayoutItemsRoute
   '/settings': typeof LayoutSettingsRoute
-  '/': typeof LayoutIndexRoute
 }
 export interface FileRoutesByTo {
   '/login': typeof LoginRoute
@@ -99,6 +99,7 @@ export interface FileRoutesById {
 export interface FileRouteTypes {
   fileRoutesByFullPath: FileRoutesByFullPath
   fullPaths:
+    | '/'
     | '/login'
     | '/recover-password'
     | '/reset-password'
@@ -106,7 +107,6 @@ export interface FileRouteTypes {
     | '/admin'
     | '/items'
     | '/settings'
-    | '/'
   fileRoutesByTo: FileRoutesByTo
   to:
     | '/login'
@@ -171,7 +171,7 @@ declare module '@tanstack/react-router' {
     '/_layout': {
       id: '/_layout'
       path: ''
-      fullPath: ''
+      fullPath: '/'
       preLoaderRoute: typeof LayoutRouteImport
       parentRoute: typeof rootRouteImport
     }