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/image.tsx

@@ -0,0 +1,24 @@
+import { cn } from "@/lib/utils";
+import type { Experimental_GeneratedImage } from "ai";
+
+export type ImageProps = Experimental_GeneratedImage & {
+  className?: string;
+  alt?: string;
+};
+
+export const Image = ({
+  base64,
+  uint8Array: _uint8Array,
+  mediaType,
+  ...props
+}: ImageProps) => (
+  <img
+    {...props}
+    alt={props.alt}
+    className={cn(
+      "h-auto max-w-full overflow-hidden rounded-md",
+      props.className
+    )}
+    src={`data:${mediaType};base64,${base64}`}
+  />
+);