feat: brand color system + Kanban view (admin + client)

- Fix button contrast: add all missing shadcn tokens (primary-foreground,
  ring, input, muted, destructive) aligned to iamcavalli brand
- NavBar: #1A463C green bar with white text
- Login page: clean brand layout with iamcavalli wordmark
- Admin pages: brand colors on headings, borders, links
- Admin ClientRow: semantic payment badges (green/yellow/red)
- Admin phases tab: Lista ↔ Kanban toggle with @dnd-kit drag & drop
  between Da fare / In corso / Fatto columns (optimistic updates)
- Client dashboard: Timeline ↔ Kanban toggle, expandable task cards
  with approve button + comment form inline

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/admin/clients/[id]/page.tsx

@@ -5,6 +5,7 @@ import { PhasesTab } from "@/components/admin/tabs/PhasesTab";
 import { PaymentsTab } from "@/components/admin/tabs/PaymentsTab";
 import { DocumentsTab } from "@/components/admin/tabs/DocumentsTab";
 import { CommentsTab } from "@/components/admin/tabs/CommentsTab";
+import { PhasesViewToggle } from "@/components/admin/kanban/PhasesViewToggle";
 import Link from "next/link";
 
 export const revalidate = 0;
@@ -51,7 +52,11 @@ export default async function ClientDetailPage({
         </TabsList>
 
         <TabsContent value="phases">
-          <PhasesTab phases={phases} clientId={client.id} />
+          <PhasesViewToggle
+            listView={<PhasesTab phases={phases} clientId={client.id} />}
+            phases={phases}
+            clientId={client.id}
+          />
         </TabsContent>
         <TabsContent value="payments">
           <PaymentsTab