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/components/admin/bulkActions/ActionModal.tsx

@@ -2,6 +2,7 @@ import { useEffect, useMemo, useRef, useState } from 'react';
 import { createPortal } from 'react-dom';
 import { useTranslation } from 'react-i18next';
 import { cn } from '@/lib/utils';
+import { CheckIcon, XCloseIcon } from '@/components/icons';
 import { useFocusTrap } from '@/hooks/useFocusTrap';
 import { DropdownSelect } from './DropdownSelect';
 import type { UserListItem } from '../../../api/adminUsers';
@@ -48,24 +49,6 @@ export interface ModalState {
   progress: ProgressState | null;
 }
 
-const CheckIcon = () => (
-  <svg
-    className="h-3 w-3 text-white"
-    fill="none"
-    viewBox="0 0 24 24"
-    stroke="currentColor"
-    strokeWidth={3}
-  >
-    <path strokeLinecap="round" strokeLinejoin="round" d="M4.5 12.75l6 6 9-13.5" />
-  </svg>
-);
-
-const XCloseIcon = () => (
-  <svg className="h-5 w-5" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-    <path strokeLinecap="round" strokeLinejoin="round" d="M6 18L18 6M6 6l12 12" />
-  </svg>
-);
-
 function ProgressView({ progress }: { progress: ProgressState }) {
   const { t } = useTranslation();
   const logEndRef = useRef<HTMLDivElement>(null);
@@ -520,7 +503,7 @@ export function ActionModal({
                     )}
                     aria-pressed={forceDeleteActivePaid}
                   >
-                    {forceDeleteActivePaid && <CheckIcon />}
+                    {forceDeleteActivePaid && <CheckIcon className="h-3 w-3" />}
                   </button>
                   <span
                     className={cn(
@@ -558,7 +541,7 @@ export function ActionModal({
                 )}
                 aria-pressed={deleteFromPanel}
               >
-                {deleteFromPanel && <CheckIcon />}
+                {deleteFromPanel && <CheckIcon className="h-3 w-3" />}
               </button>
               <span
                 className={cn(

src/components/admin/bulkActions/DropdownSelect.tsx

@@ -1,3 +1,4 @@
+import { ChevronDownIcon } from '@/components/icons';
 import { cn } from '@/lib/utils';
 
 // ──────────────────────────────────────────────────────────────────
@@ -7,11 +8,10 @@ import { cn } from '@/lib/utils';
 // chrome (border, focus ring, chevron).
 // ──────────────────────────────────────────────────────────────────
 
-export const ChevronDownIcon = () => (
-  <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
-    <path strokeLinecap="round" strokeLinejoin="round" d="M19.5 8.25l-7.5 7.5-7.5-7.5" />
-  </svg>
-);
+// Re-exported so the sibling FloatingActionBar / MultiSelectDropdown keep
+// importing the chevron from this module while the glyph itself now comes
+// from the central Phosphor barrel instead of a hand-written SVG.
+export { ChevronDownIcon };
 
 export interface DropdownOption {
   value: string;
@@ -40,7 +40,7 @@ export function DropdownSelect({ value, options, onChange, className }: Dropdown
         ))}
       </select>
       <div className="pointer-events-none absolute right-2.5 top-1/2 -translate-y-1/2 text-dark-500">
-        <ChevronDownIcon />
+        <ChevronDownIcon className="h-4 w-4" />
       </div>
     </div>
   );