fix(workspace): start the macOS rail below the traffic lights

The macOS rail reserved 36px for the traffic lights, so the first link's
hover surface touched the third light and sat above the content area.
The lights live in the 56px header band; the rail now starts its first
link at 56px, level with the content area and the dashboard hero.

A macOS Electron E2E asserts the alignment and a gap below the native
window buttons (getWindowButtonPosition); it fails with the old 36px.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/workspace/shell/feature/src/lib/workspace-shell/components/workspace-shell-rail/workspace-shell-rail.component.scss

@@ -29,8 +29,11 @@
     --rail-link-active-border: var(--app-selection-border);
     --rail-link-active-glow: var(--app-selection-glow);
 
+    // The traffic lights sit in the header band (56px, see the shell grid).
+    // The first link starts below that band, where the content area and the
+    // dashboard hero start, so its hover surface never touches the lights.
     &.is-macos {
-        padding-top: 36px;
+        padding-top: 56px;
     }
 
     &::-webkit-scrollbar {