lumiere mobile: hide sidebar to fix 2x page width

The project-list-wrapper flex row includes the sidebar (min-width:200px)
alongside the content area. On a 375px phone this totals ~575px, causing
the 2x horizontal overflow. Hide the sidebar on mobile — the filter pills
in the mobile toolbar already cover all its navigation.

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

services/web/frontend/stylesheets/pages/project-list-lumiere.scss

@@ -893,6 +893,13 @@ $lum-noise: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' wi
 
   @media (max-width: 767px) {
 
+    // The sidebar (min-width:200px) sits in a flex row with the content area,
+    // making the page ~575px wide on a 375px phone. Hide it — the filter pills
+    // in the mobile toolbar already replace all its functionality.
+    .project-list-sidebar-wrapper-react {
+      display: none !important;
+    }
+
     // Stack the header vertically so nothing overflows the viewport width.
     // Without this, lumiere-header-actions (flex-shrink:0) forces the flex
     // container wider than the screen.