feat(miniapp): add privacy consent and legal pages

Show privacy popup on launch, gate login on legal consent, and link
user agreement and privacy policy pages in the mini program.

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

miniapp/utils/api.js

@@ -1,5 +1,6 @@
 const SESSION_KEY = 'tkmind_session';
 const { createUuid, SESSION_COOKIE_NAME } = require('./config');
+const { clearLegalConsent } = require('./legal-consent');
 
 let apiBaseUrl = '';
 let cookie = '';
@@ -225,6 +226,7 @@ async function logout() {
     await portalRequest('/auth/logout', { method: 'POST' });
   } finally {
     clearSession();
+    clearLegalConsent();
   }
 }