refactor: remove unused UI components and replace GlassCard with Card in voice components

- Deleted Item, Kbd, Marker, Message, NativeSelect, Questionnaire, Spinner components.
- Replaced GlassCard with Card in VoiceActivityTimeline, VoiceConnectionCard, ListenControl, MicControl, and SpeakerWaveform components.
- Introduced AppSidebar and ThemeToggle components for improved navigation and theme management.

services/frontend/src/components/messages/ai-analysis-panel.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useState } from "react";
-import { GlassPanel } from "@/components/glass/panel";
+import { Card } from "@/components/ui/card";
 import { cn } from "@/lib/utils";
 
 interface AiAnalysisPanelProps {
@@ -37,11 +37,11 @@ export function AiAnalysisPanel({
 
   if (!status || status === "pending") {
     return (
-      <GlassPanel dense>
+      <Card className={cn("[--card-spacing:0px]", "p-3")}>
         <span className="text-xs text-text-secondary/50">
           AI analysis pending
         </span>
-      </GlassPanel>
+      </Card>
     );
   }
 
@@ -55,7 +55,7 @@ export function AiAnalysisPanel({
       : categories || [];
 
   return (
-    <GlassPanel dense className="space-y-2">
+    <Card className={cn("space-y-2", "[--card-spacing:0px]", "p-3")}>
       <div className="flex items-center gap-2">
         <span className="text-xs font-semibold tracking-wide uppercase text-text-secondary">
           AI Analysis
@@ -155,6 +155,6 @@ export function AiAnalysisPanel({
           <span className="font-mono text-accent-amber">{action}</span>
         </div>
       )}
-    </GlassPanel>
+    </Card>
   );
 }

services/frontend/src/components/messages/message-detail-view.tsx

@@ -1,9 +1,10 @@
 "use client";
 
 import { ArrowLeft, MessageSquare, MessagesSquare, Pencil } from "lucide-react";
-import { GlassCard } from "@/components/glass/card";
+import { Card } from "@/components/ui/card";
 import { getMessageChannelLabel, renderMessageContent } from "@/lib/format";
 import type { AttachmentRecord, MessageRecord } from "@/lib/types";
+import { cn } from "@/lib/utils";
 import { AiAnalysisPanel } from "./ai-analysis-panel";
 import { AttachmentsGrid } from "./attachments-grid";
 
@@ -21,7 +22,9 @@ export function MessageDetailView({
   onImageClick,
 }: MessageDetailViewProps) {
   return (
-    <GlassCard variant="base" className="h-full">
+    <Card
+      className={cn("h-full", "[--card-spacing:0px]", "rounded-2xl", "p-5")}
+    >
       {onBack && (
         <button
           type="button"
@@ -94,6 +97,6 @@ export function MessageDetailView({
         score={message.ai_moderation_score}
         analysis={message.ai_analysis}
       />
-    </GlassCard>
+    </Card>
   );
 }

services/frontend/src/components/messages/message-detail.tsx

@@ -1,9 +1,10 @@
 "use client";
 
 import { ArrowLeft, MessageSquare, MessagesSquare } from "lucide-react";
-import { GlassCard } from "@/components/glass/card";
+import { Card } from "@/components/ui/card";
 import { getMessageChannelLabel, renderMessageContent } from "@/lib/format";
 import type { AttachmentRecord, MessageRecord } from "@/lib/types";
+import { cn } from "@/lib/utils";
 import { AiAnalysisPanel } from "./ai-analysis-panel";
 import { AttachmentsGrid } from "./attachments-grid";
 
@@ -19,7 +20,9 @@ export function MessageDetail({
   onBack,
 }: MessageDetailProps) {
   return (
-    <GlassCard variant="base" className="h-full">
+    <Card
+      className={cn("h-full", "[--card-spacing:0px]", "rounded-2xl", "p-5")}
+    >
       {onBack && (
         <button
           type="button"
@@ -68,6 +71,6 @@ export function MessageDetail({
         score={message.ai_moderation_score}
         analysis={message.ai_analysis}
       />
-    </GlassCard>
+    </Card>
   );
 }