Restructure web UI navigation into 7 numbered workflow stages

Replace the flat menu (Dashboard, Audit, Validate, Burn, Benchmark,
Tasks, Tools) with a numbered progression that guides engineers through
a logical acceptance workflow:

  Dashboard (landing) → 1. Audit → 2. Check → 3. Load → 4. Speed
  → 5. Endurance → 6. Tools → 7. Settings

Key changes:
- layout.go: numbered nav labels, new hrefs, Tasks removed from nav
  and replaced with a persistent sidebar badge (polls /api/tasks every
  5 s, highlights amber when tasks are active)
- server.go: 301 redirects from /validate→/check, /burn→/load,
  /benchmark→/speed for backward compatibility
- pages.go: dispatch cases for all new routes; old routes kept as
  fallbacks
- page_validate.go: add renderCheck() — non-destructive check page
  with validate-mode tests only (no stress toggle, no targeted-stress/
  targeted-power/pulse cards)
- page_burn.go: add renderLoad() wrapper; update scope alert to
  reference /check instead of /validate
- page_benchmark.go: add renderSpeed() (performance focus) and
  renderEndurance() (stability/overnight focus) wrappers
- page_settings.go: new Settings page with blackbox logging toggle,
  NVIDIA driver reset, and build info
- server_test.go: update five tests to use new route names and
  content expectations

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

audit/internal/webui/page_settings.go

@@ -0,0 +1,77 @@
+package webui
+
+import "html"
+
+func renderSettings(opts HandlerOptions) string {
+	version := opts.BuildLabel
+	if version == "" {
+		version = "dev"
+	}
+	return `<div class="grid2">
+
+<div class="card">
+  <div class="card-head">Blackbox Logging</div>
+  <div class="card-body">
+    <p style="font-size:13px;color:var(--muted);margin-bottom:14px">Continuous hardware monitoring that writes a rolling log of sensor readings to the export directory. Useful for capturing thermal or power anomalies during long runs.</p>
+    <div style="display:flex;gap:8px;align-items:center">
+      <button class="btn btn-primary btn-sm" onclick="blackboxToggle('enable')">Enable</button>
+      <button class="btn btn-secondary btn-sm" onclick="blackboxToggle('disable')">Disable</button>
+      <span id="blackbox-status" style="font-size:12px;color:var(--muted)">Loading...</span>
+    </div>
+  </div>
+</div>
+
+<div class="card">
+  <div class="card-head">NVIDIA Recovery</div>
+  <div class="card-body">
+    <p style="font-size:13px;color:var(--muted);margin-bottom:14px">Reset NVIDIA GPU driver state. Use when <code>nvidia-smi</code> reports errors or GPUs appear stuck after a failed test.</p>
+    <div style="display:flex;gap:8px;align-items:center">
+      <button class="btn btn-danger btn-sm" onclick="nvidiaReset()">Reset NVIDIA Driver</button>
+      <span id="nvidia-reset-status" style="font-size:12px;color:var(--muted)"></span>
+    </div>
+  </div>
+</div>
+
+</div>
+
+<div class="card" style="margin-top:0">
+  <div class="card-head">Build Info</div>
+  <div class="card-body">
+    <table style="width:auto">
+      <tbody>
+        <tr><td style="color:var(--muted);padding-right:24px">Version</td><td>` + html.EscapeString(version) + `</td></tr>
+        <tr><td style="color:var(--muted);padding-right:24px">Title</td><td>` + html.EscapeString(opts.Title) + `</td></tr>
+      </tbody>
+    </table>
+  </div>
+</div>
+
+<script>
+(function() {
+  fetch('/api/blackbox/status', {cache:'no-store'}).then(r => r.json()).then(d => {
+    var el = document.getElementById('blackbox-status');
+    if (el) el.textContent = d.enabled ? 'Enabled' : 'Disabled';
+  }).catch(() => {
+    var el = document.getElementById('blackbox-status');
+    if (el) el.textContent = 'Status unavailable';
+  });
+})();
+function blackboxToggle(action) {
+  var el = document.getElementById('blackbox-status');
+  if (el) el.textContent = 'Updating...';
+  fetch('/api/blackbox/' + action, {method:'POST', cache:'no-store'})
+    .then(r => r.json())
+    .then(d => { if (el) el.textContent = d.enabled ? 'Enabled' : 'Disabled'; })
+    .catch(err => { if (el) el.textContent = 'Error: ' + err.message; });
+}
+function nvidiaReset() {
+  var el = document.getElementById('nvidia-reset-status');
+  if (!confirm('Reset NVIDIA driver? This will interrupt any running GPU tasks.')) return;
+  if (el) el.textContent = 'Resetting...';
+  fetch('/api/gpu/nvidia-reset', {method:'POST', cache:'no-store'})
+    .then(r => r.json())
+    .then(d => { if (el) el.textContent = d.error ? ('Error: ' + d.error) : 'Done — driver reset.'; })
+    .catch(err => { if (el) el.textContent = 'Error: ' + err.message; });
+}
+</script>`
+}