fix(browser): align list columns via subgrid and fix icon sizing

- Switch .browser-list to CSS grid + subgrid so header and rows share
  the same column track widths, eliminating misaligned columns when
  content widths differ between rows.
- Apply matching responsive column overrides at the parent grid level.
- Override root-folder SVG sizing (hardcoded 24x24 in browser.js) so it
  fills the 56px icon box instead of rendering at ~43%.
- Make compact grid icon fill its thumb wrapper so the emoji centers
  instead of being stranded in the top-left corner.
- Remove premature isConnected bail in loadThumbnail; the img element
  is intentionally detached when called from renderBrowserGrid/List.
  Post-await checks already handle navigation-away correctly.

media_server/static/css/styles.css

@@ -3077,19 +3077,25 @@ button.primary svg {
 
 /* Browser List View */
 .browser-list {
-    display: flex;
-    flex-direction: column;
-    gap: 1px;
+    display: grid;
+    grid-template-columns: 40px 1fr auto auto auto auto;
+    column-gap: 1.25rem;
+    row-gap: 1px;
     margin-bottom: 1.5rem;
     min-height: 200px;
 }
 
+.browser-list > .browser-empty,
+.browser-list > .browser-loading {
+    grid-column: 1 / -1;
+}
+
 /* List view column header */
 .browser-list-header {
     display: grid;
-    grid-template-columns: 40px 1fr auto auto auto auto;
+    grid-template-columns: subgrid;
+    grid-column: 1 / -1;
     align-items: center;
-    gap: 0.75rem;
     padding: 0.4rem 0.75rem;
     font-size: 0.688rem;
     font-weight: 600;
@@ -3107,9 +3113,9 @@ button.primary svg {
 
 .browser-list-item {
     display: grid;
-    grid-template-columns: 40px 1fr auto auto auto auto;
+    grid-template-columns: subgrid;
+    grid-column: 1 / -1;
     align-items: center;
-    gap: 0.75rem;
     padding: 0.5rem 0.75rem;
     background: transparent;
     border: 1px solid transparent;
@@ -3303,6 +3309,13 @@ button.primary svg {
     transition: all 0.25s;
 }
 
+/* Root folder SVG ships with hardcoded width=24 height=24 (browser.js folderSvg),
+   which renders at ~43% of the 56px icon box. Override to fill it properly. */
+.browser-item.browser-root-folder .browser-icon > svg {
+    width: 60%;
+    height: 60%;
+}
+
 .browser-item.browser-root-folder:hover .browser-icon {
     background: rgba(var(--copper-rgb), 0.18);
     border-color: rgba(var(--copper-rgb), 0.3);
@@ -3650,9 +3663,12 @@ button.primary svg {
         display: none;
     }
 
-    .browser-list-header {
+    .browser-list {
         grid-template-columns: 32px 1fr auto auto;
-        gap: 0.5rem;
+        column-gap: 0.875rem;
+    }
+
+    .browser-list-header {
         padding: 0.35rem 0.5rem;
     }
 
@@ -3661,8 +3677,6 @@ button.primary svg {
     }
 
     .browser-list-item {
-        grid-template-columns: 32px 1fr auto auto;
-        gap: 0.5rem;
         padding: 0.4rem 0.5rem;
     }
 
@@ -3732,17 +3746,13 @@ button.primary svg {
         display: none;
     }
 
-    .browser-list-header {
+    .browser-list {
         grid-template-columns: 40px 1fr auto auto auto;
     }
 
     .browser-list-header span:nth-child(3) {
         display: none;
     }
-
-    .browser-list-item {
-        grid-template-columns: 40px 1fr auto auto auto;
-    }
 }
 
 /* Update Banner */
@@ -7405,9 +7415,15 @@ select option {
     font-size: 9px;
     letter-spacing: 0.1em;
 }
+/* Let the compact icon fill its thumb-wrapper (matches grid view behaviour).
+   The previous 28x28 size left the icon stranded at the wrapper's top-left
+   because .browser-thumb-wrapper is not a flex container. The wrapper square
+   is sized by the grid; the emoji inside .browser-icon centers via the base
+   flex rules. */
 .browser-container .browser-grid-compact .browser-icon {
-    width: 28px;
-    height: 28px;
+    width: 100%;
+    height: 100%;
+    font-size: 2.25rem;
 }
 .browser-container .browser-item {
     background: transparent !important;