feat: add recordings, settings, and voice pages with WebSocket integration

- Implemented RecordingsPage to display and manage voice recordings with live updates via WebSocket.
- Created SettingsPage for user preferences, including theme toggling and server configuration display.
- Developed VoicePage for managing voice connections, including guild and channel selection, and active speaker display.
- Introduced GuildSelector component for selecting Discord guilds with error handling and loading states.
- Added utility functions for formatting numbers and bytes, and safely parsing JSON.
- Established navigation structure for the dashboard with relevant links for new features.

services/frontend/src/lib/navigation.ts

@@ -0,0 +1,75 @@
+import {
+  BarChart3,
+  Headphones,
+  LayoutDashboard,
+  MessageSquare,
+  Mic,
+  Music,
+  Search,
+  type LucideIcon,
+} from "lucide-react";
+
+export interface NavItem {
+  href: string;
+  label: string;
+  icon: LucideIcon;
+  /** The pathname prefix that indicates this item is active */
+  matchPrefix: string;
+}
+
+/**
+ * Primary navigation items shown in the sidebar.
+ */
+export const navItems: NavItem[] = [
+  {
+    href: "/dashboard",
+    label: "Dashboard",
+    icon: LayoutDashboard,
+    matchPrefix: "/dashboard",
+  },
+  {
+    href: "/messages",
+    label: "Messages",
+    icon: MessageSquare,
+    matchPrefix: "/messages",
+  },
+  {
+    href: "/voice",
+    label: "Voice",
+    icon: Mic,
+    matchPrefix: "/voice",
+  },
+  {
+    href: "/media",
+    label: "Media",
+    icon: Music,
+    matchPrefix: "/media",
+  },
+  {
+    href: "/recordings",
+    label: "Recordings",
+    icon: Headphones,
+    matchPrefix: "/recordings",
+  },
+  {
+    href: "/analysis",
+    label: "Search",
+    icon: Search,
+    matchPrefix: "/analysis",
+  },
+  {
+    href: "/settings",
+    label: "Settings",
+    icon: BarChart3,
+    matchPrefix: "/settings",
+  },
+];
+
+/**
+ * Mobile bottom bar items (subset of primary nav).
+ */
+export const mobileNavItems: NavItem[] = navItems.filter((item) =>
+  ["/dashboard", "/messages", "/voice", "/media"].includes(item.href),
+);
+
+export type NavItemId = (typeof navItems)[number]["href"];