feat(ui): make favicons user-configurable, off by default

- Add favicon service preference: None (default), Google, DuckDuckGo
- result_item.html: remove hardcoded Google favicon src, defer to JS
- applyFavicon() reads data-domain attr and sets src or display:none
- Privacy-by-default: users must explicitly opt in to any favicon service
- Add favicon selector to both the settings panel and preferences page

internal/views/static/js/settings.js

@@ -7,7 +7,8 @@ var DEFAULT_PREFS = {
   theme: 'system',
   engines: ALL_ENGINES.slice(),
   safeSearch: 'moderate',
-  format: 'html'
+  format: 'html',
+  favicon: 'none' // 'none' | 'google' | 'duckduckgo'
 };
 
 var STORAGE_KEY = 'kafka_prefs';
@@ -22,7 +23,8 @@ function loadPrefs() {
         theme: parsed.theme || DEFAULT_PREFS.theme,
         engines: parsed.engines || DEFAULT_PREFS.engines.slice(),
         safeSearch: parsed.safeSearch || DEFAULT_PREFS.safeSearch,
-        format: parsed.format || DEFAULT_PREFS.format
+        format: parsed.format || DEFAULT_PREFS.format,
+        favicon: parsed.favicon || DEFAULT_PREFS.favicon
       };
     } catch (e) {
       prefs = DEFAULT_PREFS;
@@ -43,6 +45,24 @@ function applyTheme(theme) {
   }
 }
 
+function applyFavicon(service) {
+  var faviconMap = {
+    google: function(domain) { return 'https://www.google.com/s2/favicons?domain=' + encodeURIComponent(domain) + '&sz=32'; },
+    duckduckgo: function(domain) { return 'https://icons.duckduckgo.com/ip3/' + encodeURIComponent(domain) + '.ico'; }
+  };
+  var imgs = document.querySelectorAll('.result-favicon');
+  imgs.forEach(function(img) {
+    var domain = img.getAttribute('data-domain');
+    if (!domain) return;
+    if (service === 'none') {
+      img.style.display = 'none';
+    } else {
+      img.style.display = '';
+      img.src = faviconMap[service](domain);
+    }
+  });
+}
+
 function syncEngineInput(prefs) {
   var input = document.getElementById('engines-input');
   if (input) {
@@ -104,6 +124,13 @@ function renderPanel(prefs) {
   });
 
   
+  var faviconOptions = '';
+  ['none', 'google', 'duckduckgo'].forEach(function(src) {
+    var labels = { none: 'None', google: 'Google', duckduckgo: 'DuckDuckGo' };
+    var selected = prefs.favicon === src ? ' selected' : '';
+    faviconOptions += '<option value="' + src + '"' + selected + '>' + labels[src] + '</option>';
+  });
+
   body.innerHTML =
     '<div class="settings-section">' +
       '<div class="settings-section-title">Appearance</div>' +
@@ -124,6 +151,10 @@ function renderPanel(prefs) {
         '<label for="pref-format">Default format</label>' +
         '<select id="pref-format">' + fmtOptionsHtml + '</select>' +
       '</div>' +
+      '<div class="setting-row">' +
+        '<label for="pref-favicon">Favicon service</label>' +
+        '<select id="pref-favicon">' + faviconOptions + '</select>' +
+      '</div>' +
     '</div>';
 
   // Theme buttons
@@ -162,6 +193,7 @@ function renderPanel(prefs) {
 function initSettings() {
   var prefs = loadPrefs();
   applyTheme(prefs.theme);
+  applyFavicon(prefs.favicon);
   syncEngineInput(prefs);
   renderPanel(prefs);
 
@@ -257,6 +289,9 @@ function initPreferences() {
   // Load saved preferences
   var prefs = loadPrefs();
 
+  // Apply favicon settings immediately on preferences page
+  applyFavicon(prefs.favicon);
+
   // Theme
   var themeEl = document.getElementById('pref-theme');
   if (themeEl) {
@@ -288,6 +323,17 @@ function initPreferences() {
     });
   }
 
+  // Favicon service (if exists on page)
+  var faviconEl = document.getElementById('pref-favicon');
+  if (faviconEl) {
+    faviconEl.value = prefs.favicon || 'none';
+    faviconEl.addEventListener('change', function() {
+      prefs.favicon = faviconEl.value;
+      savePrefs(prefs);
+      applyFavicon(prefs.favicon);
+    });
+  }
+
   // Show first section by default
   showSection('search');
 }

internal/views/templates/preferences.html

@@ -69,6 +69,17 @@
           <option value="2">Strict</option>
         </select>
       </div>
+      <div class="pref-row">
+        <div class="pref-row-info">
+          <label>Favicon Service</label>
+          <p class="pref-desc">Fetch favicons for result URLs. "None" is most private.</p>
+        </div>
+        <select name="favicon" id="pref-favicon">
+          <option value="none" selected>None</option>
+          <option value="google">Google</option>
+          <option value="duckduckgo">DuckDuckGo</option>
+        </select>
+      </div>
     </section>
 
     <section class="pref-section">

internal/views/templates/result_item.html

@@ -4,7 +4,7 @@
     <a href="{{.URL}}" target="_blank" rel="noopener noreferrer">{{.SafeTitle}}</a>
   </div>
   <div class="result_url">
-    <img class="result-favicon" src="https://www.google.com/s2/favicons?domain={{.URL | urlquery}}&sz=32" alt="" loading="lazy" onerror="this.style.display='none'">
+    <img class="result-favicon" data-domain="{{.URL}}" src="" alt="" loading="lazy" style="display:none">
     <a href="{{.URL}}" target="_blank" rel="noopener noreferrer">{{.URL}}</a>
     <span class="engine-badge" data-engine="{{.Engine}}">{{.Engine}}</span>
   </div>