fix: polish download status and application menus

Animate nested application menus while keeping hidden actions out of keyboard navigation and respecting reduced-motion preferences.

Normalize Mega-Debrid service labels, simplify active download and extraction statuses, and preserve full diagnostics in tooltips.

Brand the Windows development runtime and isolate concurrent launchers with PID-aware cleanup and regression coverage.

src/renderer/shell/shell.css

@@ -612,6 +612,22 @@
 .md-application-menu-tree .menu-submenu-dropdown {
   right: 100%;
   left: auto;
+  opacity: 0;
+  transform: translateX(8px);
+  visibility: hidden;
+  pointer-events: none;
+  transition:
+    opacity 160ms ease,
+    transform 220ms cubic-bezier(0.22, 0.76, 0.22, 1),
+    visibility 0s linear 220ms;
+}
+
+.md-application-menu-tree .menu-submenu-dropdown.is-open {
+  opacity: 1;
+  transform: translateX(0);
+  visibility: visible;
+  pointer-events: auto;
+  transition-delay: 0s;
 }
 
 .md-overlay-host {
@@ -909,4 +925,13 @@
   .md-application-menu-tree .menu-dropdown.is-open {
     transition-delay: 0s !important;
   }
+
+  .md-application-menu-tree .menu-submenu-dropdown {
+    transition-duration: 0.01ms !important;
+    transition-delay: 0s !important;
+  }
+
+  .md-application-menu-tree .menu-submenu-dropdown.is-open {
+    transition-delay: 0s !important;
+  }
 }