feat: initialize smirk-website with connect flow

- Next.js 16 with TypeScript and Tailwind CSS
- Single-asset authentication (user picks favorite coin to sign)
- Logo with glow animation
- Coin picker UI with all 5 assets
- API client for backend auth endpoints
- TypeScript types for window.smirk extension API

src/lib/api.ts

@@ -0,0 +1,75 @@
+// API client for Smirk backend
+
+const API_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3000';
+
+export interface ChallengeResponse {
+  challenge: string;
+  challenge_id: string;
+  expires_at: string;
+}
+
+export interface AuthResponse {
+  access_token: string;
+  refresh_token: string;
+  expires_in: number;
+  user: {
+    id: string;
+    telegram_id: number | null;
+    telegram_username: string | null;
+  };
+}
+
+export interface MeResponse {
+  id: string;
+  username: string | null;
+  telegram_id: number | null;
+  telegram_username: string | null;
+}
+
+export async function getChallenge(origin: string): Promise<ChallengeResponse> {
+  const res = await fetch(`${API_URL}/api/v1/auth/website/challenge`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ origin }),
+  });
+
+  if (!res.ok) {
+    const error = await res.json().catch(() => ({ message: 'Request failed' }));
+    throw new Error(error.message || 'Failed to get challenge');
+  }
+
+  return res.json();
+}
+
+export async function verifySignature(
+  challengeId: string,
+  signature: { asset: string; signature: string; public_key: string }
+): Promise<AuthResponse> {
+  const res = await fetch(`${API_URL}/api/v1/auth/website/verify`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      challenge_id: challengeId,
+      signature,
+    }),
+  });
+
+  if (!res.ok) {
+    const error = await res.json().catch(() => ({ message: 'Request failed' }));
+    throw new Error(error.message || 'Failed to verify signature');
+  }
+
+  return res.json();
+}
+
+export async function getMe(token: string): Promise<MeResponse> {
+  const res = await fetch(`${API_URL}/api/v1/auth/me`, {
+    headers: { Authorization: `Bearer ${token}` },
+  });
+
+  if (!res.ok) {
+    throw new Error('Failed to get user info');
+  }
+
+  return res.json();
+}