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/primitives/Dialog/Dialog.tsx

@@ -8,6 +8,7 @@ import {
   useState,
 } from 'react';
 import { cn } from '@/lib/utils';
+import { CloseIcon } from '@/components/icons';
 import { backdrop, backdropTransition, scale, scaleTransition } from '../../motion/transitions';
 
 export {
@@ -16,19 +17,6 @@ export {
   Close as DialogClose,
 } from '@radix-ui/react-dialog';
 
-// Close icon
-const CloseIcon = () => (
-  <svg width="16" height="16" viewBox="0 0 16 16" fill="none">
-    <path
-      d="M12 4L4 12M4 4l8 8"
-      stroke="currentColor"
-      strokeWidth="1.5"
-      strokeLinecap="round"
-      strokeLinejoin="round"
-    />
-  </svg>
-);
-
 // Context for AnimatePresence
 const DialogContext = createContext<{ open: boolean }>({ open: false });