feat: visual polish, nav login link, pricing badge fix, cursor fix, button contrast

- Hero mockup: enhanced 3D perspective and shadow
- Testimonials: illustrated SVG avatars
- Growth pricing card: visual prominence (scale, gradient, badge)
- Most Popular badge: repositioned to avoid overlapping heading
- Nav: added Log In link next to Start Free Trial
- Fixed btn-primary text colour on anchor tags (white on blue)
- Fixed cursor: default on all non-interactive elements
- Disabled user-select on non-form content to prevent text caret

public/auth.js

@@ -0,0 +1,110 @@
+/**
+ * TenderRadar Authentication Utilities
+ * Shared auth module for all app pages
+ */
+
+/**
+ * Get JWT token from localStorage
+ * @returns {string|null} JWT token or null if not found
+ */
+function getToken() {
+  return localStorage.getItem('tenderradar_token');
+}
+
+/**
+ * Set JWT token in localStorage
+ * @param {string} token - JWT token to store
+ */
+function setToken(token) {
+  localStorage.setItem('tenderradar_token', token);
+}
+
+/**
+ * Clear JWT token from localStorage
+ */
+function clearToken() {
+  localStorage.removeItem('tenderradar_token');
+}
+
+/**
+ * Check if user is authenticated
+ * @returns {boolean} true if token exists, false otherwise
+ */
+function isAuthenticated() {
+  return !!getToken();
+}
+
+/**
+ * Decode JWT payload (simple, does not verify signature)
+ * @returns {object|null} Decoded payload or null if token invalid
+ */
+function getUserInfo() {
+  const token = getToken();
+  if (!token) return null;
+
+  try {
+    const parts = token.split('.');
+    if (parts.length !== 3) return null;
+
+    const payload = JSON.parse(atob(parts[1]));
+    return payload;
+  } catch (e) {
+    console.error('Failed to decode token:', e);
+    return null;
+  }
+}
+
+/**
+ * Redirect to login if not authenticated
+ */
+function requireAuth() {
+  if (!isAuthenticated()) {
+    window.location.href = '/login.html';
+  }
+}
+
+/**
+ * Fetch with automatic Authorization header
+ * @param {string} url - API endpoint URL
+ * @param {object} options - Fetch options
+ * @returns {Promise<Response>} Fetch response
+ */
+async function fetchWithAuth(url, options = {}) {
+  const token = getToken();
+  
+  const headers = {
+    'Content-Type': 'application/json',
+    ...options.headers
+  };
+
+  if (token) {
+    headers['Authorization'] = `Bearer ${token}`;
+  }
+
+  return fetch(url, {
+    ...options,
+    headers
+  });
+}
+
+/**
+ * Logout user: clear token and redirect to login
+ */
+function logout() {
+  clearToken();
+  window.location.href = '/login.html';
+}
+
+// Export for use as ES module
+if (typeof module !== 'undefined' && module.exports) {
+  module.exports = {
+    getToken,
+    setToken,
+    clearToken,
+    isAuthenticated,
+    getUserInfo,
+    requireAuth,
+    fetchWithAuth,
+    logout
+  };
+}