fix: multiple Dashboard CSS defects (dead rules, contrast, responsive)

- The desktop rule that hides the row ⋮ button ended two selectors with a
  comma before an @media block, so the whole construct was invalid and
  discarded — the ⋮ showed on every list-view row on desktop instead of
  deferring to right-click. Verified: it's now hidden (display:none).
- Native-drop dark-mode styles keyed off .window[data-color-scheme="dark"],
  an attribute never set anywhere; converted to @media (prefers-color-scheme:
  dark) like every other dark rule so they actually apply.
- .myapps-tile-label set white-space:nowrap after a 2-line -webkit-line-clamp,
  defeating the clamp so long app names clipped mid-glyph on one line;
  removed it.
- .dashboard-sidebar-separator was defined a second time with a contradicting
  box model (background line + full-width margin), rendering a doubled,
  edge-to-edge divider; removed the duplicate so the inset border rule stands.
- Grid-view .item-icon had a hardcoded background:white and border-radius:2px
  overriding its own border-radius:8px (glaring white tiles in dark mode,
  square-ish corners); use var(--dashboard-background) and keep 8px.
- .files-footer used hardcoded #666/#CCC on theme-variable backgrounds
  (dim in dark, near-invisible separator in light); use the text/muted vars.
- Fixed the .ui-droppable-over typo (jQuery UI emits ui-droppable-hover).
- The context-menu backdrop's "desktop transparent" rule used min-width:768px
  while every mobile rule uses max-width:768px, overlapping at exactly 768px
  (a common tablet width) — a non-dimming, invisible modal shield; bumped to
  769px.
- At 481-768px the fixed hamburger toggle sat on top of the Files directories
  column's first folder because .dashboard-content.files padding wins over the
  media-query padding; add top clearance to the directories column there.

Verified light-mode desktop is unchanged (directories padding still 16px, ⋮
hidden, footer colors resolve).

src/gui/src/css/dashboard.css

@@ -952,7 +952,6 @@ input.myapps-search::-webkit-search-decoration {
     -webkit-line-clamp: 2;
     -webkit-box-orient: vertical;
     word-break: break-word;
-    white-space: nowrap;
 }
 
 /* Uninstall confirmation modal */
@@ -1815,7 +1814,7 @@ body.myapps-reordering .myapps-tile {
 }
 
 .dashboard-section-files .row.folder.ui-droppable-hover,
-.dashboard-section-files .row.folder.selected.ui-droppable-over {
+.dashboard-section-files .row.folder.selected.ui-droppable-hover {
     color: var(--dashboard-text);
     background-color: rgba(59, 130, 246, 0.1);
     border: 2px dashed var(--select-color);
@@ -1901,14 +1900,16 @@ body.myapps-reordering .myapps-tile {
 }
 
 /* Dark mode support for native file drop */
-.window[data-color-scheme="dark"] .dashboard-section-files .files.native-drop-active {
-    background-color: rgba(100, 180, 255, 0.12);
-    outline-color: #4da3ff;
-}
+@media (prefers-color-scheme: dark) {
+    .dashboard-section-files .files.native-drop-active {
+        background-color: rgba(100, 180, 255, 0.12);
+        outline-color: #4da3ff;
+    }
 
-.window[data-color-scheme="dark"] .dashboard-section-files .directories li.native-drop-target,
-.window[data-color-scheme="dark"] .dashboard-section-files .files .row.folder.native-drop-target {
-    background-color: rgba(100, 180, 255, 0.2);
+    .dashboard-section-files .directories li.native-drop-target,
+    .dashboard-section-files .files .row.folder.native-drop-target {
+        background-color: rgba(100, 180, 255, 0.2);
+    }
 }
 
 .dashboard-section-files .files-footer {
@@ -1926,7 +1927,7 @@ body.myapps-reordering .myapps-tile {
     align-items: center;
     justify-content: center;
     gap: 8px;
-    color: #666;
+    color: var(--dashboard-text-secondary);
     z-index: 10;
 }
 
@@ -1936,7 +1937,7 @@ body.myapps-reordering .myapps-tile {
 }
 
 .dashboard-section-files .files-footer-separator {
-    color: #CCC;
+    color: var(--dashboard-text-muted);
 }
 
 /* Floating Selection Actions Bar */
@@ -2179,11 +2180,9 @@ body.myapps-reordering .myapps-tile {
     display: flex;
     align-items: center;
     justify-content: center;
-    /* background: #fafafa; */
+    background: var(--dashboard-background);
     border-radius: 8px;
     overflow: hidden;
-    background: white;
-    border-radius: 2px;
 }
 
 .dashboard-section-files .files-tab .files.files-grid-view .row .item-icon img {
@@ -2242,11 +2241,9 @@ body.myapps-reordering .myapps-tile {
 /* Hide .item-more on desktop (non-touch devices) - use right-click context menu instead */
 .dashboard-section-files .files-tab:not(.touch-device) .files.files-list-view .row .item-more,
 .dashboard-section-files .files-tab:not(.touch-device) .files.files-grid-view .row .item-more,
-@media (hover: hover) {
-    .dashboard-section-files .files-tab:not(.touch-device) .files.files-grid-view .row:hover .item-more,
-    .dashboard-section-files .files-tab:not(.touch-device) .header .columns .item-more {
-        display: none !important;
-    }
+.dashboard-section-files .files-tab:not(.touch-device) .files.files-grid-view .row:hover .item-more,
+.dashboard-section-files .files-tab:not(.touch-device) .header .columns .item-more {
+    display: none !important;
 }
 
 .dashboard-section-files .files-tab .files.files-grid-view .row .item-name-editor {
@@ -2444,12 +2441,6 @@ body.myapps-reordering .myapps-tile {
     transform: rotate(-45deg) translate(4px, -4px);
 }
 
-.dashboard-sidebar-separator {
-    height: 1px;
-    background: var(--dashboard-border);
-    margin: 15px 0;
-}
-
 /* Responsive: tablet and below */
 @media (max-width: 768px) {
     .dashboard-sidebar-header {
@@ -2486,6 +2477,15 @@ body.myapps-reordering .myapps-tile {
         padding: 64px 16px 24px;
     }
 
+    /* The Files tab keeps its own `padding: 0 0 0 10px` (higher specificity)
+       so the rule above doesn't clear the fixed hamburger toggle for it. Push
+       the directories column down instead, so the toggle doesn't sit on top of
+       the first folder row (the column is hidden below 480px, so this only
+       affects the tablet range). */
+    .dashboard-section-files .directories {
+        padding-top: 52px;
+    }
+
     .myapps-search-wrap {
         padding-top: 60px;
         margin-bottom: 10px;
@@ -3999,8 +3999,10 @@ body.myapps-reordering .myapps-tile {
     opacity: 0.8;
 }
 
-/* Desktop - transparent backdrop */
-@media (min-width: 768px) {
+/* Desktop - transparent backdrop. Use 769px so it doesn't overlap the mobile
+   rules (all keyed to max-width: 768px) at exactly 768px, where a touch tablet
+   would otherwise get a fully transparent, non-dimming modal backdrop. */
+@media (min-width: 769px) {
     .context-menu-modal-backdrop {
         background-color: transparent;
     }