fix: add mobile menu to projects view and CSS

public/js/views/projects.js

@@ -17,11 +17,21 @@ export async function renderProjects(app) {
   function render() {
     appEl.innerHTML = `
       <header class="app-header">
+        <button class="mobile-nav-btn" onclick="toggleMobileMenu()" title="Menu">☰</button>
         <div class="logo">📝 SimpleNote</div>
         <div class="header-actions">
           <button class="btn btn-primary" onclick="window.showNewProjectModal()">+ New</button>
         </div>
       </header>
+      <div class="mobile-menu" id="mobile-menu">
+        <div class="mobile-menu-header">
+          <span>Menu</span>
+          <button onclick="closeMobileMenu()">✕</button>
+        </div>
+        <div class="mobile-menu-content">
+          <a href="#" onclick="closeMobileMenu(); return false;">📋 All Projects</a>
+        </div>
+      </div>
       <div class="projects-page">
         <div class="projects-header">
           <h1>Projects</h1>
@@ -137,4 +147,15 @@ window.showNewProjectModal = function() {
   };
 
   nameInput.focus();
+}
+
+// Mobile menu functions
+window.toggleMobileMenu = function() {
+  const menu = document.getElementById('mobile-menu');
+  if (menu) menu.classList.toggle('open');
+};
+
+window.closeMobileMenu = function() {
+  const menu = document.getElementById('mobile-menu');
+  if (menu) menu.classList.remove('open');
 };