Story 5.2: Video Widget Width Customization

Implements configurable video widget widths for small and large dock layouts:
- Add widgetWidthSm and widgetWidthMd world settings (defaults: 83px, 150px)
- Add width dropdown selectors in Director's Board UI
- Apply width settings to participant avatars via CSS custom properties
- Update strip width/height calculations to use custom widths
- Add localization strings for widget width settings
- Add CSS styling for widget width dropdown controls
- Fix Handlebars template syntax for select element selected values

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

templates/directors-board.hbs

@@ -78,6 +78,29 @@
     </div>
   </div>
 
+  {{!-- Story 5.2: Video widget width customization --}}
+  <div class="directors-board__widget-width-bar" role="toolbar" aria-label="{{localize 'scrying-pool.directorsBoard.widgetWidth.label'}}">
+    <span class="directors-board__widget-width-label">{{localize "scrying-pool.directorsBoard.widgetWidth.label"}}</span>
+    <div class="directors-board__widget-width-group">
+      <div class="directors-board__widget-width-row">
+        <span>{{localize "scrying-pool.directorsBoard.widgetWidth.small"}}</span>
+        <select class="directors-board__widget-width-select" data-action="set-widget-width-sm" data-selected="{{widgetWidthSm}}">
+          {{#each widthOptions}}
+            <option value="{{this.value}}">{{this.label}}</option>
+          {{/each}}
+        </select>
+      </div>
+      <div class="directors-board__widget-width-row">
+        <span>{{localize "scrying-pool.directorsBoard.widgetWidth.large"}}</span>
+        <select class="directors-board__widget-width-select" data-action="set-widget-width-md" data-selected="{{widgetWidthMd}}">
+          {{#each widthOptions}}
+            <option value="{{this.value}}">{{this.label}}</option>
+          {{/each}}
+        </select>
+      </div>
+    </div>
+  </div>
+
   <footer class="directors-board__footer">
     <div class="directors-board__footer-group directors-board__footer-group--presets">
       <button type="button" class="directors-board__footer-btn" data-action="save-preset"