fix: portfolio value formula, Yahoo UA header, mobile nav hamburger

- Remove erroneous /100 in currentValue calculation (portfolio values
  were 100x too small, causing net worth card to show ~€0)
- Add User-Agent header to Yahoo Finance requests (avoids 429s)
- Wrap ES module chart body in if(total>0){} block (return at top
  level of a module is a SyntaxError — chart was silently broken)
- Add mobile hamburger menu: full-screen drawer at ≤720px with
  animated open/close, all nav links, scroll lock while open

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/finance/services/api/main/templates/base.html

@@ -413,17 +413,67 @@
     .animate-on-scroll:nth-child(4) { transition-delay: 0.21s; }
     .animate-on-scroll:nth-child(5) { transition-delay: 0.28s; }
 
+    /* ── Hamburger / mobile drawer ────────────────────────────────────── */
+    .nav-hamburger {
+      display: none;
+      width: 36px; height: 36px;
+      border: none; background: none; cursor: pointer;
+      color: var(--text2);
+      flex-direction: column; justify-content: center; align-items: center; gap: 5px;
+      border-radius: var(--radius-sm);
+      transition: background 0.18s;
+    }
+    .nav-hamburger:hover { background: var(--surface2); }
+    .nav-hamburger span {
+      display: block; width: 20px; height: 2px;
+      background: currentColor; border-radius: 2px;
+      transition: transform 0.25s ease, opacity 0.25s ease;
+    }
+    .nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
+    .nav-hamburger.open span:nth-child(2) { opacity: 0; }
+    .nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
+
+    .nav-drawer {
+      display: none;
+      position: fixed; inset: var(--nav-h) 0 0 0;
+      background: var(--bg);
+      z-index: 199;
+      overflow-y: auto;
+      padding: 12px 16px 32px;
+      flex-direction: column; gap: 4px;
+      animation: slideIn 0.2s ease-out both;
+    }
+    .nav-drawer.open { display: flex; }
+    .nav-drawer a, .nav-drawer-section-label {
+      display: block;
+      padding: 11px 14px;
+      border-radius: var(--radius-sm);
+      font-size: 15px; font-weight: 500;
+      color: var(--text2); text-decoration: none;
+      transition: all 0.15s;
+    }
+    .nav-drawer a:hover { color: var(--text); background: var(--surface2); }
+    .nav-drawer a.active { color: var(--accent2); background: var(--accent-glow); }
+    .nav-drawer-section-label {
+      font-size: 11px; font-weight: 600; letter-spacing: 0.08em;
+      text-transform: uppercase; color: var(--text3);
+      padding-top: 16px; padding-bottom: 4px;
+    }
+    .nav-drawer hr { border: none; border-top: 1px solid var(--border); margin: 8px 0; }
+
     /* ── Responsive ──────────────────────────────────────────────────── */
     @media (max-width: 900px) {
       .grid-2 { grid-template-columns: 1fr; }
     }
-    @media (max-width: 600px) {
+    @media (max-width: 720px) {
-      .nav { padding: 0 12px; gap: 2px; overflow-x: auto; }
+      .nav-hamburger { display: flex; }
-      .nav a:not(.nav-brand) { padding: 6px 7px; font-size: 12px; }
+      .nav > a:not(.nav-brand),
+      .nav > .nav-group,
+      .nav > .nav-spacer,
+      .nav-email { display: none; }
       .container { padding: 16px 12px 32px; }
       .grid { grid-template-columns: 1fr 1fr; }
       .card { padding: 16px; }
-      .nav-email { display: none; }
     }
   </style>
 </head>
@@ -469,8 +519,32 @@
     <div class="nav-spacer"></div>
     <span class="nav-email">{{.Email}}</span>
     <button class="theme-btn" id="theme-toggle" title="Toggle dark/light mode">🌙</button>
+    <button class="nav-hamburger" id="nav-hamburger" aria-label="Menu">
+      <span></span><span></span><span></span>
+    </button>
   </nav>
 
+  <!-- Mobile drawer -->
+  <div class="nav-drawer" id="nav-drawer">
+    <a href="/"             class="{{if eq .Route "dashboard"}}active{{end}}">Dashboard</a>
+    <a href="/transactions" class="{{if eq .Route "transactions"}}active{{end}}">Transactions</a>
+    <a href="/portfolio"    class="{{if eq .Route "portfolio"}}active{{end}}">Portfolio</a>
+    <a href="/goals"        class="{{if eq .Route "goals"}}active{{end}}">Goals</a>
+    <a href="/people"       class="{{if eq .Route "people"}}active{{end}}">People</a>
+    <hr>
+    <span class="nav-drawer-section-label">Analysis</span>
+    <a href="/reports"     class="{{if eq .Route "reports"}}active{{end}}">Reports</a>
+    <a href="/projections" class="{{if eq .Route "projections"}}active{{end}}">Projections</a>
+    <a href="/tax"         class="{{if eq .Route "tax"}}active{{end}}">Tax</a>
+    <a href="/networth"    class="{{if eq .Route "networth"}}active{{end}}">Net Worth</a>
+    <a href="/simulator"   class="{{if eq .Route "simulator"}}active{{end}}">What If</a>
+    <hr>
+    <span class="nav-drawer-section-label">Settings</span>
+    <a href="/settings?tab=accounts" class="{{if eq .Route "settings"}}active{{end}}">Accounts &amp; Categories</a>
+    <a href="/import"                class="{{if eq .Route "import"}}active{{end}}">Import CSV</a>
+    <a href="/auto-import"           class="{{if eq .Route "auto-import"}}active{{end}}">Import Guide</a>
+  </div>
+
   <div class="container">
     {{block "content" .}}{{end}}
   </div>
@@ -493,6 +567,22 @@
     btn.addEventListener('click', () =>
       applyTheme(html.getAttribute('data-theme') === 'dark' ? 'light' : 'dark'));
 
+    /* ── Mobile hamburger ─────────────────────────────────────────── */
+    const hamburger = document.getElementById('nav-hamburger');
+    const drawer    = document.getElementById('nav-drawer');
+    hamburger.addEventListener('click', () => {
+      const open = drawer.classList.toggle('open');
+      hamburger.classList.toggle('open', open);
+      document.body.style.overflow = open ? 'hidden' : '';
+    });
+    drawer.querySelectorAll('a').forEach(a =>
+      a.addEventListener('click', () => {
+        drawer.classList.remove('open');
+        hamburger.classList.remove('open');
+        document.body.style.overflow = '';
+      })
+    );
+
     /* ── Animated counter ─────────────────────────────────────────── */
     function animateCounter(el) {
       const target   = parseFloat(el.getAttribute('data-target'));