Build temetro app: dark theme, clinical sidebar, AI chat, settings page

- Linear-inspired dark theme (app/globals.css), forced dark in layout
- Clinical sidebar (components/sidebar-02) with temetro brand
- AI chat UI (components/chat): Cursor-style input, UI-only mock replies
- Settings page (components/settings): Polar-style tabs/sections, UI only
- Route-group app shell: app/(app)/{layout,page,settings}
- shadcn (Base UI) + ai-elements component libraries
- CLAUDE.md: architecture notes + per-folder commit policy

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

frontend/components/ai-elements/sources.tsx

@@ -0,0 +1,77 @@
+"use client";
+
+import {
+  Collapsible,
+  CollapsibleContent,
+  CollapsibleTrigger,
+} from "@/components/ui/collapsible";
+import { cn } from "@/lib/utils";
+import { BookIcon, ChevronDownIcon } from "lucide-react";
+import type { ComponentProps } from "react";
+
+export type SourcesProps = ComponentProps<"div">;
+
+export const Sources = ({ className, ...props }: SourcesProps) => (
+  <Collapsible
+    className={cn("not-prose mb-4 text-primary text-xs", className)}
+    {...props}
+  />
+);
+
+export type SourcesTriggerProps = ComponentProps<typeof CollapsibleTrigger> & {
+  count: number;
+};
+
+export const SourcesTrigger = ({
+  className,
+  count,
+  children,
+  ...props
+}: SourcesTriggerProps) => (
+  <CollapsibleTrigger
+    className={cn("flex items-center gap-2", className)}
+    {...props}
+  >
+    {children ?? (
+      <>
+        <p className="font-medium">Used {count} sources</p>
+        <ChevronDownIcon className="h-4 w-4" />
+      </>
+    )}
+  </CollapsibleTrigger>
+);
+
+export type SourcesContentProps = ComponentProps<typeof CollapsibleContent>;
+
+export const SourcesContent = ({
+  className,
+  ...props
+}: SourcesContentProps) => (
+  <CollapsibleContent
+    className={cn(
+      "mt-3 flex w-fit flex-col gap-2",
+      "data-[state=closed]:fade-out-0 data-[state=closed]:slide-out-to-top-2 data-[state=open]:slide-in-from-top-2 outline-none data-[state=closed]:animate-out data-[state=open]:animate-in",
+      className
+    )}
+    {...props}
+  />
+);
+
+export type SourceProps = ComponentProps<"a">;
+
+export const Source = ({ href, title, children, ...props }: SourceProps) => (
+  <a
+    className="flex items-center gap-2"
+    href={href}
+    rel="noreferrer"
+    target="_blank"
+    {...props}
+  >
+    {children ?? (
+      <>
+        <BookIcon className="h-4 w-4" />
+        <span className="block font-medium">{title}</span>
+      </>
+    )}
+  </a>
+);