refactor(desktop): restructure pages and consolidate UI components

- Rename channels.tsx to clients.tsx
- Remove standalone skills.tsx and tools.tsx pages
- Add agent/ directory for agent-related pages
- Update layout and navigation structure
- Add tabs component to ui package
- Update fonts and global styles

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/ui/src/components/ui/tabs.tsx

@@ -0,0 +1,82 @@
+"use client"
+
+import { Tabs as TabsPrimitive } from "@base-ui/react/tabs"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@multica/ui/lib/utils"
+
+function Tabs({
+  className,
+  orientation = "horizontal",
+  ...props
+}: TabsPrimitive.Root.Props) {
+  return (
+    <TabsPrimitive.Root
+      data-slot="tabs"
+      data-orientation={orientation}
+      className={cn(
+        "gap-2 group/tabs flex data-horizontal:flex-col",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+const tabsListVariants = cva(
+  "rounded-lg p-[3px] group-data-horizontal/tabs:h-8 data-[variant=line]:rounded-none group/tabs-list text-muted-foreground inline-flex w-fit items-center justify-center group-data-vertical/tabs:h-fit group-data-vertical/tabs:flex-col",
+  {
+    variants: {
+      variant: {
+        default: "bg-muted",
+        line: "gap-1 bg-transparent",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+)
+
+function TabsList({
+  className,
+  variant = "default",
+  ...props
+}: TabsPrimitive.List.Props & VariantProps<typeof tabsListVariants>) {
+  return (
+    <TabsPrimitive.List
+      data-slot="tabs-list"
+      data-variant={variant}
+      className={cn(tabsListVariants({ variant }), className)}
+      {...props}
+    />
+  )
+}
+
+function TabsTrigger({ className, ...props }: TabsPrimitive.Tab.Props) {
+  return (
+    <TabsPrimitive.Tab
+      data-slot="tabs-trigger"
+      className={cn(
+        "gap-1.5 rounded-md border border-transparent px-1.5 py-0.5 text-sm font-medium group-data-[variant=default]/tabs-list:data-active:shadow-sm group-data-[variant=line]/tabs-list:data-active:shadow-none [&_svg:not([class*='size-'])]:size-4 focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:outline-ring text-foreground/60 hover:text-foreground dark:text-muted-foreground dark:hover:text-foreground relative inline-flex h-[calc(100%-1px)] flex-1 items-center justify-center whitespace-nowrap transition-all group-data-vertical/tabs:w-full group-data-vertical/tabs:justify-start focus-visible:ring-[3px] focus-visible:outline-1 disabled:pointer-events-none disabled:opacity-50 aria-disabled:pointer-events-none aria-disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:shrink-0",
+        "group-data-[variant=line]/tabs-list:bg-transparent group-data-[variant=line]/tabs-list:data-active:bg-transparent dark:group-data-[variant=line]/tabs-list:data-active:border-transparent dark:group-data-[variant=line]/tabs-list:data-active:bg-transparent",
+        "data-active:bg-background dark:data-active:text-foreground dark:data-active:border-input dark:data-active:bg-input/30 data-active:text-foreground",
+        "after:bg-foreground after:absolute after:opacity-0 after:transition-opacity group-data-horizontal/tabs:after:inset-x-0 group-data-horizontal/tabs:after:bottom-[-5px] group-data-horizontal/tabs:after:h-0.5 group-data-vertical/tabs:after:inset-y-0 group-data-vertical/tabs:after:-right-1 group-data-vertical/tabs:after:w-0.5 group-data-[variant=line]/tabs-list:data-active:after:opacity-100",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TabsContent({ className, ...props }: TabsPrimitive.Panel.Props) {
+  return (
+    <TabsPrimitive.Panel
+      data-slot="tabs-content"
+      className={cn("text-sm flex-1 outline-none", className)}
+      {...props}
+    />
+  )
+}
+
+export { Tabs, TabsList, TabsTrigger, TabsContent, tabsListVariants }