fix: add Thumbnail field and video result template

MainResult: add Thumbnail field (used by YouTube, images, etc.)
video_item.html: new partial for video results with thumbnail display
views.go: add templateForResult func + video_item.html to template parse
results_inner.html: dispatch to video_item when Template="videos"
kafka.css: add .video-result flex layout with thumbnail styling

internal/views/templates/results_inner.html

@@ -52,7 +52,7 @@
 <div id="urls" role="main">
   {{if .Results}}
   {{range .Results}}
-  {{template "result_item" .}}
+  {{template (templateForResult .Template) .}}
   {{end}}
   {{else if not .Answers}}
   <div class="no_results">

internal/views/templates/video_item.html

@@ -0,0 +1,22 @@
+{{define "video_item"}}
+<article class="result video-result">
+  {{if .Thumbnail}}
+  <div class="result_thumbnail">
+    <a href="{{.URL}}" target="_blank" rel="noopener noreferrer">
+      <img src="{{.Thumbnail}}" alt="{{.Title}}" loading="lazy">
+    </a>
+  </div>
+  {{end}}
+  <div class="result_content_wrapper">
+    <h3 class="result_header">
+      <a href="{{.URL}}" target="_blank" rel="noopener noreferrer">{{.Title}}</a>
+    </h3>
+    {{if .Content}}
+    <p class="result_content">{{.Content}}</p>
+    {{end}}
+    {{if .Engine}}
+    <div class="result_engine"><span class="engine">{{.Engine}}</span></div>
+    {{end}}
+  </div>
+</article>
+{{end}}