lumiere: fix mobile overflow + restore tile view with XS/M/L zoom

Overflow fix: ActionsCell (up to 9 icon buttons) was assigned to the
`auto` column in the compact row, blowing out the row to ~300px.
Replace with ActionsDropdown (single ⋮ button) on mobile via
d-md-none / d-none d-md-flex, same pattern as the classic table.

Tile view: remove the isMobile force to compact (effectiveScale=0).
Add a mobile-only toolbar row (d-flex d-md-none) combining the filter
pills and a new XS/M/L zoom control:
  - XS (scale=0)  → compact rows
  - M  (scale=1)  → 2 tiles per row  (CSS: repeat(2, 1fr))
  - L  (scale≥1.35) → 1 tile per row (CSS: 1fr, class --mobile-1col)

The --lum-card-scale inline var is suppressed on mobile so CSS media
query controls thumbnail height (0.85 for 2-col, 1.3 for 1-col).

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

services/web/frontend/js/features/project-list/components/project-list-lumiere.tsx

@@ -41,6 +41,7 @@ import FormatCell from './table/cells/format-cell'
 import OwnerCell from './table/cells/owner-cell'
 import LastUpdatedCell from './table/cells/last-updated-cell'
 import ActionsCell from './table/cells/actions-cell'
+import ActionsDropdown from './dropdown/actions-dropdown'
 import InlineTags from './table/cells/inline-tags'
 import WelcomePageContent from './welcome-page-content'
 
@@ -68,6 +69,12 @@ const ZOOM_OPTIONS: { value: ZoomLevel; label: string }[] = [
   { value: 1.35, label: 'M' },
   { value: 1.75, label: 'L' },
 ]
+// Mobile offers 3 sizes: XS (rows), M (2 tiles), L (1 tile)
+const MOBILE_ZOOM_OPTIONS: { value: ZoomLevel; label: string }[] = [
+  { value: 0, label: 'XS' },
+  { value: 1, label: 'M' },
+  { value: 1.35, label: 'L' },
+]
 const ZOOM_STORAGE_KEY = 'lumiere-card-scale'
 
 function useLumiereCardScale(): [ZoomLevel, (z: ZoomLevel) => void] {
@@ -245,9 +252,15 @@ const ProjectCardCompact = memo(function ProjectCardCompact({
         </div>
       </div>
       <div className="lumiere-compact-actions">
+        {/* ⋮ dropdown on mobile (single button), icon strip on desktop */}
+        <div className="d-md-none">
+          <ActionsDropdown project={project} />
+        </div>
+        <div className="d-none d-md-flex">
           <ActionsCell project={project} />
         </div>
       </div>
+    </div>
   )
 })
 
@@ -271,8 +284,14 @@ export function ProjectListLumiere() {
     selectFilter,
   } = useProjectListContext()
 
-  // On mobile, always use the compact (XS) row view — cards overflow on small screens
-  const effectiveScale = isMobile ? 0 : cardScale
+  // On mobile: M option (scale=1) → 2 tiles/row; L (scale≥1.35) → 1 tile/row.
+  // CSS overrides the card grid columns on mobile; we only add a class for L.
+  const mobileIsL = isMobile && cardScale !== 0 && cardScale >= 1.35
+  const activeMobileZoom = cardScale === 0
+    ? 0
+    : cardScale >= 1.35
+      ? 1.35
+      : 1
 
   const selectedTag = tags.find(tag => tag._id === selectedTagId)
   const allSelected =
@@ -351,8 +370,13 @@ export function ProjectListLumiere() {
                     ))}
                   </div>
                 </div>
-                {/* Mobile-only filter pills replacing the hidden sidebar */}
-                <div className="d-flex d-md-none lumiere-mobile-filters" role="group" aria-label={t('filter_projects')}>
+                {/* Mobile-only: filter pills + zoom control */}
+                <div className="d-flex d-md-none lumiere-mobile-toolbar">
+                  <div
+                    className="lumiere-mobile-filters"
+                    role="group"
+                    aria-label={t('filter_projects')}
+                  >
                     {MOBILE_FILTERS.map(({ f, label }) => (
                       <button
                         key={f}
@@ -365,6 +389,24 @@ export function ProjectListLumiere() {
                       </button>
                     ))}
                   </div>
+                  <div
+                    className="lumiere-zoom-control lumiere-mobile-zoom"
+                    role="group"
+                    aria-label={t('card_size')}
+                  >
+                    {MOBILE_ZOOM_OPTIONS.map(({ value, label }) => (
+                      <button
+                        key={value}
+                        type="button"
+                        className={`lumiere-zoom-btn${activeMobileZoom === value ? ' active' : ''}`}
+                        onClick={() => setCardScale(value)}
+                        aria-pressed={activeMobileZoom === value}
+                      >
+                        {label}
+                      </button>
+                    ))}
+                  </div>
+                </div>
                 <div className="lumiere-header-actions">
                   <SearchForm
                     inputValue={searchText}
@@ -410,12 +452,16 @@ export function ProjectListLumiere() {
                 <p className="lumiere-empty">{t('no_projects')}</p>
               ) : (
                 <div
-                  className={`lumiere-card-grid${effectiveScale === 0 ? ' lumiere-card-grid--compact' : ''}`}
+                  className={[
+                    'lumiere-card-grid',
+                    cardScale === 0 && 'lumiere-card-grid--compact',
+                    mobileIsL && 'lumiere-card-grid--mobile-1col',
+                  ].filter(Boolean).join(' ')}
                   // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
-                  style={effectiveScale === 0 ? {} : ({ '--lum-card-scale': effectiveScale } as React.CSSProperties)}
+                  style={cardScale === 0 || isMobile ? {} : ({ '--lum-card-scale': cardScale } as React.CSSProperties)}
                 >
                   {visibleProjects.map(project =>
-                    effectiveScale === 0 ? (
+                    cardScale === 0 ? (
                       <ProjectCardCompact key={project.id} project={project} />
                     ) : (
                       <ProjectCard key={project.id} project={project} />

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

@@ -870,12 +870,15 @@ $lum-noise: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' wi
     opacity: 1;
   }
 
-  // ── Mobile compact row — 2-line layout ────────────────────────────────────
-  // On small screens the 6-column grid overflows. Switch to:
-  //   Row 1: [checkbox] [name+tags]  [actions]
-  //   Row 2: [checkbox] [format · owner · date]
+  // ── Mobile layout overrides ────────────────────────────────────────────────
 
   @media (max-width: 767px) {
+
+    // Compact row: 2-line layout
+    // Row 1: [checkbox] [name+tags]  [⋮ action]
+    // Row 2: [checkbox] [format · owner · date]
+    // ActionsDropdown (single ⋮ button) is shown via d-md-none; ActionsCell
+    // (many icon buttons) is hidden on mobile, so the auto column stays tiny.
     .lumiere-compact-row {
       grid-template-columns: 28px 1fr auto;
       grid-template-rows: auto auto;
@@ -896,6 +899,9 @@ $lum-noise: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' wi
         grid-column: 3;
         grid-row: 1;
         align-self: center;
+        opacity: 1;
+
+        .action-btn { opacity: 1; }
       }
 
       // Meta wrapper becomes a flex row spanning the second line
@@ -907,30 +913,49 @@ $lum-noise: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' wi
         grid-column: 2 / 4;
         grid-row: 2;
       }
-
-      // Actions always visible — no hover on touch devices
-      @media (hover: none) {
-        .lumiere-compact-actions .action-btn {
-          opacity: 1;
     }
+
+    // Card tile grid: M = 2 tiles/row, L = 1 tile/row.
+    // --lum-card-scale inline var is suppressed on mobile (isMobile=true in JS),
+    // so the CSS custom property here wins for thumbnail sizing.
+    .lumiere-card-grid:not(.lumiere-card-grid--compact) {
+      grid-template-columns: repeat(2, 1fr);
+      gap: 0.75rem;
+      --lum-card-scale: 0.85;
+
+      &.lumiere-card-grid--mobile-1col {
+        grid-template-columns: 1fr;
+        --lum-card-scale: 1.3;
       }
     }
   }
 
-  // ── Mobile filter pills (replaces hidden sidebar on xs/sm) ────────────────
+  // ── Mobile toolbar: filter pills + zoom control ───────────────────────────
+
+  .lumiere-mobile-toolbar {
+    align-items: center;
+    gap: 0.5rem;
+    width: 100%;
+    padding: 0.25rem 0 0.5rem;
+    flex-shrink: 0;
+  }
 
   .lumiere-mobile-filters {
     overflow-x: auto;
+    display: flex;
     gap: 0.45rem;
-    padding: 0.25rem 0 0.5rem;
+    flex: 1;
+    min-width: 0;
     scrollbar-width: none;
     -ms-overflow-style: none;
-    flex-shrink: 0;
-    width: 100%;
 
     &::-webkit-scrollbar { display: none; }
   }
 
+  .lumiere-mobile-zoom {
+    flex-shrink: 0;
+  }
+
   .lumiere-mobile-filter-pill {
     flex-shrink: 0;
     padding: 0.3rem 0.8rem;