refactor(frontend): major rebuild — feature-sliced architecture + bug fixes + glass-morphism UI

Architecture:
- Feature-sliced directory: entities/, shared/, features/, widgets/
- Consolidated API client (shared/api/client.ts) — all endpoints in one file
- Single WebSocket manager (shared/ws/socket.ts) with typed event bus
- Extracted hooks: useAudioPlayback, useAudioTransmit, useLocalStorage, useUIState
- UI primitives moved to shared/ui/ with barrel export
- Added Skeleton, Toast, MobileTabBar components

Bug fixes (8/8):
1. useMemo→useEffect in RecordingsSubPanel (async side-effect anti-pattern)
2. ArrayBuffer.slice() before WebSocket send (shared buffer bug)
3. Proper useEffect dependency arrays throughout
4. Stable React keys (no index fallbacks)
5. onReanalyze properly awaited (Promise<void> return)
6. monitorGuild memoized with useMemo
7. localStorage validation with shape checking
8. Deleted duplicate socket logic (ws/client.ts removed)

UI polish:
- Glass-morphism design tokens (backdrop-blur, translucent cards)
- Gradient mesh background with subtle radial overlays
- Expandable sidebar + mobile bottom tab bar
- Skeleton loading placeholders
- Audio visualizer with CSS pulse animation

Deleted: src/api/, src/components/, src/hooks/, src/types/, src/ws/, src/lib/
Added: 40 new files across feature-sliced structure

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/features/analytics/components/TopicList.tsx

@@ -0,0 +1,76 @@
+import { Flame } from "lucide-react";
+import type { TopicTrend } from "../../../shared/api/client";
+import { Card, CardContent, CardDescription, CardHeader, CardTitle, ScrollArea } from "../../../shared/ui";
+
+interface TopicListProps {
+  topics: TopicTrend[];
+  loading: boolean;
+}
+
+export function TopicList({ topics, loading }: TopicListProps) {
+  if (loading && !topics?.length) {
+    return <LoadingBox />;
+  }
+
+  if (!topics?.length) {
+    return (
+      <Card>
+        <CardContent className="flex h-[260px] items-center justify-center text-sm text-muted-foreground">
+          Topik akan muncul setelah AI selesai menganalisis.
+        </CardContent>
+      </Card>
+    );
+  }
+
+  const maxCount = Math.max(...topics.map((t) => t.count), 1);
+
+  return (
+    <Card>
+      <CardHeader className="pb-2">
+        <CardTitle className="flex items-center gap-2 text-sm font-semibold">
+          <Flame className="h-4 w-4 text-orange-400" />
+          Topik Trending
+        </CardTitle>
+        <CardDescription className="text-xs">
+          Yang paling ramai dibicarakan.
+        </CardDescription>
+      </CardHeader>
+      <CardContent className="p-0">
+        <ScrollArea className="max-h-[260px]">
+          <div className="divide-y divide-border/30">
+            {topics.map((topic, i) => (
+              <div key={topic.topic} className="flex items-center gap-3 px-5 py-2 text-sm">
+                <span className="w-5 shrink-0 text-right font-mono text-[10px] text-muted-foreground">
+                  {i + 1}
+                </span>
+                <span className="flex-1 truncate font-medium">{topic.topic}</span>
+                <div className="flex items-center gap-2">
+                  <div className="h-1.5 w-12 overflow-hidden rounded-full bg-muted">
+                    <div
+                      className="h-full rounded-full bg-blue-500/60"
+                      style={{ width: `${(topic.count / maxCount) * 100}%` }}
+                    />
+                  </div>
+                  <span className="w-8 text-right font-mono text-xs tabular-nums text-muted-foreground">
+                    {topic.count}
+                  </span>
+                </div>
+              </div>
+            ))}
+          </div>
+        </ScrollArea>
+      </CardContent>
+    </Card>
+  );
+}
+
+function LoadingBox() {
+  return (
+    <Card>
+      <CardContent className="flex h-[260px] items-center justify-center text-sm text-muted-foreground">
+        <span className="h-4 w-4 animate-spin rounded-full border-2 border-current border-t-transparent" />
+        <span className="ml-2">Memuat data...</span>
+      </CardContent>
+    </Card>
+  );
+}