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/globals.css

@@ -4,28 +4,60 @@
 @source not "../../scripts/**";
 
 /* =========================================================
-   Design tokens — light & clean palette (Tailwind v4 @theme)
+   Design tokens — iamcavalli brand palette (Tailwind v4 @theme)
    ========================================================= */
 @theme inline {
-  /* Colori base */
-  --color-background: #ffffff;
-  --color-foreground: #171717;
-
   /* Font */
   --font-sans: var(--font-geist-sans), system-ui, -apple-system, BlinkMacSystemFont,
     "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
   --font-mono: var(--font-geist-mono);
 
-  /* Palette brand iamcavalli — light & clean */
-  --color-primary:      #1a1a1a; /* charcoal per testo principale */
-  --color-secondary:    #666666; /* grigio medio per testo secondario */
-  --color-tertiary:     #999999; /* grigio chiaro per hint e timestamp */
-  --color-bg-subtle:    #f9f9f9; /* grigio molto chiaro per sfondi sezione */
-  --color-border-light: #e5e5e5; /* bordo sottile */
-  --color-accent:       #0066cc; /* blu accent */
-  --color-success:      #16a34a; /* verde per done/saldato */
-  --color-warning:      #ca8a04; /* giallo per in_progress/inviata */
-  --color-info:         #2563eb; /* blu per pending/da_saldare */
+  /* Base */
+  --color-background:   #ffffff;
+  --color-foreground:   #1a1a1a;
+
+  /* Brand primary — verde scuro iamcavalli */
+  --color-primary:             #1A463C;
+  --color-primary-foreground:  #ffffff;
+
+  /* Brand accent — giallo lime */
+  --color-accent:              #DEF168;
+  --color-accent-foreground:   #1A463C;
+
+  /* Secondary — grigio neutro */
+  --color-secondary:           #f4f4f5;
+  --color-secondary-foreground: #1a1a1a;
+
+  /* Muted — per testi e sfondi secondari */
+  --color-muted:               #f9f9f9;
+  --color-muted-foreground:    #71717a;
+
+  /* Destructive */
+  --color-destructive:             #ef4444;
+  --color-destructive-foreground:  #ffffff;
+
+  /* Card */
+  --color-card:             #ffffff;
+  --color-card-foreground:  #1a1a1a;
+
+  /* Popover */
+  --color-popover:             #ffffff;
+  --color-popover-foreground:  #1a1a1a;
+
+  /* Border / Input / Ring */
+  --color-border: #e5e7eb;
+  --color-input:  #e5e7eb;
+  --color-ring:   #1A463C;
+
+  /* Semantic — stato task/pagamenti */
+  --color-success: #16a34a;
+  --color-warning: #ca8a04;
+  --color-info:    #2563eb;
+
+  /* Legacy — usati inline nei componenti esistenti */
+  --color-tertiary:     #999999;
+  --color-bg-subtle:    #f9f9f9;
+  --color-border-light: #e5e5e5;
 }
 
 /* =========================================================