feat(cabinet): migrate all icons to the panel's Phosphor set

Replace the cabinet's hand-written heroicons-style SVG icon components with
the Remnawave panel's own icon family — Phosphor via react-icons/pi (Duotone).
All icons now live in a single central barrel (src/components/icons:
index + extended-icons + editor-icons, 144 icons); every feature file imports
from it instead of redefining inline SVGs (~440 icon defs removed).

- Add react-icons dependency
- Desktop nav (AppShell) now uses the central Phosphor icons, removing a
  stroke-vs-duotone inconsistency the partial migration introduced
- Icons with custom props (SortIcon's direction, expandable chevrons) kept as
  thin Phosphor wrappers; the RemnawaveIcon brand logo and animated SVGs
  (checkmarks, spinners) are intentionally left as-is
- Restore the original per-call-site icon sizes wherever the centralized
  default differed (211 call sites)

src/pages/Balance.tsx

@@ -12,26 +12,10 @@ import type { PaginatedResponse, Transaction } from '../types';
 
 import { Card } from '@/components/data-display/Card';
 import { Button } from '@/components/primitives/Button';
-import { ChevronDownIcon, ChevronRightIcon, CreditCardIcon } from '@/components/icons';
+import { ChevronDownIcon, ChevronRightIcon, CreditCardIcon, WalletIcon } from '@/components/icons';
 import { staggerContainer, staggerItem } from '@/components/motion/transitions';
 import { isPaidStatus, isFailedStatus } from '../utils/paymentStatus';
 
-const WalletIcon = ({ className = 'h-8 w-8' }: { className?: string }) => (
-  <svg
-    className={className}
-    fill="none"
-    viewBox="0 0 24 24"
-    stroke="currentColor"
-    strokeWidth={1.5}
-  >
-    <path
-      strokeLinecap="round"
-      strokeLinejoin="round"
-      d="M2.25 18.75a60.07 60.07 0 0115.797 2.101c.727.198 1.453-.342 1.453-1.096V18.75M3.75 4.5v.75A.75.75 0 013 6h-.75m0 0v-.375c0-.621.504-1.125 1.125-1.125H20.25M2.25 6v9m18-10.5v.75c0 .414.336.75.75.75h.75m-1.5-1.5h.375c.621 0 1.125.504 1.125 1.125v9.75c0 .621-.504 1.125-1.125 1.125h-.375m1.5-1.5H21a.75.75 0 00-.75.75v.75m0 0H3.75m0 0h-.375a1.125 1.125 0 01-1.125-1.125V15m1.5 1.5v-.75A.75.75 0 003 15h-.75M15 10.5a3 3 0 11-6 0 3 3 0 016 0zm3 0h.008v.008H18V10.5zm-12 0h.008v.008H6V10.5z"
-    />
-  </svg>
-);
-
 export default function Balance() {
   const { t } = useTranslation();
   const refreshUser = useAuthStore((state) => state.refreshUser);