fix: ensure HTML response for downloads polling

- Added html=1 parameter to downloads HTMX polling
- Fixed data structure mismatch between backend and Jinja2 template
- Guaranteed TemplateResponse for downloads list when requested

templates/components/downloads_list.html

@@ -1,9 +1,9 @@
 <div class="downloads-grid" 
-     hx-get="/api/downloads?html=true" 
+     hx-get="/api/downloads?html=1" 
      hx-trigger="every 2s" 
      hx-swap="innerHTML">
     {% if tasks %}
-        {% for task_id, task in tasks.items() %}
+        {% for task in tasks %}
             <div class="download-item task-{{ task.status }}">
                 <div class="download-info">
                     <span class="download-name" title="{{ task.filename }}">{{ task.filename }}</span>
@@ -16,29 +16,29 @@
                 
                 <div class="download-meta">
                     <span>{{ task.progress | round(1) }}%</span>
-                    <span>{{ task.download_speed }}</span>
-                    <span>{{ task.eta }}</span>
+                    <span>{{ task.speed or '0' }} KB/s</span>
+                    <span>{{ task.eta or '' }}</span>
                 </div>
                 
                 <div class="download-actions">
                     {% if task.status == 'downloading' or task.status == 'pending' %}
-                        <button class="btn-icon" hx-post="/api/downloads/{{ task_id }}/pause" hx-swap="none">
+                        <button class="btn-icon" hx-post="/api/downloads/{{ task.id }}/pause" hx-swap="none">
                             <i class="fas fa-pause"></i>
                         </button>
                     {% elif task.status == 'paused' %}
-                        <button class="btn-icon" hx-post="/api/downloads/{{ task_id }}/resume" hx-swap="none">
+                        <button class="btn-icon" hx-post="/api/downloads/{{ task.id }}/resume" hx-swap="none">
                             <i class="fas fa-play"></i>
                         </button>
                     {% endif %}
                     
                     {% if task.status == 'completed' %}
-                        <a href="/video/{{ task_id }}" class="btn-icon success">
+                        <a href="/video/{{ task.id }}" class="btn-icon success">
                             <i class="fas fa-external-link-alt"></i>
                         </a>
                     {% endif %}
                     
                     <button class="btn-icon danger" 
-                            hx-delete="/api/downloads/{{ task_id }}" 
+                            hx-delete="/api/downloads/{{ task.id }}" 
                             hx-confirm="Supprimer ce téléchargement ?"
                             hx-swap="none">
                         <i class="fas fa-trash"></i>