feat: complete server-backed six-lesson app and trial tooling

Co-authored-by: Cursor <cursoragent@cursor.com>

src/api/token.ts

@@ -0,0 +1,22 @@
+const TOKEN_KEY = 'gold-land-auth-token'
+
+let authToken: string | null = null
+
+export function getAuthToken(): string | null {
+  if (authToken) return authToken
+  try {
+    return localStorage.getItem(TOKEN_KEY)
+  } catch {
+    return null
+  }
+}
+
+export function setAuthToken(token: string | null) {
+  authToken = token
+  try {
+    if (token) localStorage.setItem(TOKEN_KEY, token)
+    else localStorage.removeItem(TOKEN_KEY)
+  } catch {
+    // ignore
+  }
+}