feat(admin): design system audit fixes

- Add CSS design tokens for consistency (--admin-danger-hover, --admin-accent-dot, shadow-md warm tone)
- Replace unicode icons with inline SVG (⋮, ✕, ▼, ▶)
- Consolidate duplicate PageHeader/AdminPageHeader components
- Standardize border-radius (rounded-xl → rounded-lg for ViewModeTabs)
- Remove hardcoded brand UUID in products page
- Replace hardcoded bg-red-600 with CSS variables in delete buttons
- Add AdminButton, AdminFilterTabs, AdminSearchInput, PageHeader design system components
- Fix GlassModal and AdminModal close button styling
- Remove duplicate 'New Lot' button on Route Trace dashboard

src/styles/admin-design-system.css

@@ -17,20 +17,22 @@
   --admin-border: #d0cbb4;           /* parchment 400 */
   --admin-border-light: #e5e2d9;    /* soft_linen */
   
-  /* Accent - Powder Petal (warm coral/peach) */
-  --admin-accent: #ca7543;           /* powder_petal 300 */
-  --admin-accent-hover: #8c4c27;     /* powder_petal 200 */
-  --admin-accent-light: #f4e3d9;     /* powder_petal 600 */
-  --admin-accent-text: #8c4c27;      /* powder_petal 200 */
+  /* Accent - Fresh Produce Green */
+  --admin-accent: #16a34a;           /* green-600 - fresh produce brand */
+  --admin-accent-hover: #15803d;     /* green-700 */
+  --admin-accent-light: #dcfce7;     /* green-100 */
+  --admin-accent-text: #166534;      /* green-800 */
   
   /* Status Colors */
-  --admin-success: #726e67;          /* dim_grey 300 */
-  --admin-success-accent: #535350;   /* dim_grey 400 */
+  --admin-success: #16a34a;          /* green-600 - fresh produce success */
+  --admin-success-accent: #15803d;   /* green-700 */
   --admin-warning: #aba278;          /* parchment 300 */
   --admin-warning-light: #f5f4ef;    /* parchment */
-  --admin-danger: #8c4c27;           /* powder_petal 200 */
-  --admin-danger-light: #f4e3d9;    /* powder_petal 600 */
+  --admin-danger: #dc2626;           /* red-600 */
+  --admin-danger-hover: #b91c1c;     /* red-700 */
+  --admin-danger-light: #fef2f2;     /* red-50 */
   --admin-info: #686763;             /* dim_grey */
+  --admin-accent-dot: #22c55e;       /* green-500 */
   
   /* Sidebar - Dark elegant */
   --admin-sidebar-bg: #3c3825;       /* parchment 100 */
@@ -50,7 +52,7 @@
   
   /* Shadows - subtle warm shadows */
   --admin-shadow-sm: 0 1px 2px rgba(60, 56, 37, 0.04);
-  --admin-shadow-md: 0 4px 6px -1px rgba(60, 56, 37, 0.06), 0 2px 4px -2px rgba(60, 56, 37, 0.04);
+  --admin-shadow-md: 0 4px 12px rgba(60, 56, 37, 0.08);
   --admin-shadow-lg: 0 10px 15px -3px rgba(60, 56, 37, 0.08), 0 4px 6px -4px rgba(60, 56, 37, 0.04);
 }
 
@@ -282,12 +284,12 @@
 }
 
 .admin-status--active {
-  background-color: #dcfce7; /* green-100 */
-  color: #166534; /* green-800 */
+  background-color: var(--admin-accent-light);
+  color: var(--admin-accent-text);
 }
 
 .admin-status--active::before {
-  background-color: #22c55e; /* green-500 */
+  background-color: var(--admin-accent-dot);
 }
 
 .admin-status--inactive {