feat(frontend): skeleton loading states, empty-state glow, light-mode polish

- Add shared skeleton building blocks (SkeletonHero, SkeletonMetricRow,
  SkeletonPanel, SkeletonRows) and wire them into every view's initial
  loading branch, replacing bare spinners for a cohesive shimmering shell.
- Polish EmptyState with a glow-ring icon chip instead of a flat icon.
- Harden .light theme: color-scheme, tuned scrollbar + selection for pale
  canvas. Dark/light theme toggle (next-themes) already persisted in TopBar.

services/frontend/src/app/(dashboard)/messages/view.tsx

@@ -22,8 +22,8 @@ import {
 import {
   EmptyState,
   ErrorState,
-  LoadingState,
   SectionHeader,
+  SkeletonRows,
 } from "@/components/shared";
 import { GuildChannelPicker } from "@/components/shared/guild-picker";
 import {
@@ -185,7 +185,7 @@ export function MessagesView({
           {error && !messages ? (
             <ErrorState error={error} />
           ) : isLoading && !messages ? (
-            <LoadingState label="Capturing" />
+            <SkeletonRows rows={8} />
           ) : list.length === 0 ? (
             <EmptyState
               icon={<MessageSquare className="size-7" />}