feat: account management overhaul + 7 issue resolutions (#147)

- Add smart JSON export/import with schema validation and deduplication
- Add per-account proxy configurations (Issue #79)
- Add advanced account sorting engine (Issues #126 & #99)
- Add compact horizontal layout, AI credits, inline model visibility (Issues #145 & #134)
- Add desktop push notifications for low quota (Issue #53)
- Fix Arch Linux AUR process detection bug (Issue #117)
- Default theme set to Dark Mode (it's better)
- UI Polishing: Improved sort dropdown and symmetrical dialog layouts
- Dev Mode: Resolved port conflicts and single-instance locks
- Updated README and README.zh-CN with new features

src/components/ui/dropdown-menu.tsx

@@ -48,21 +48,38 @@ DropdownMenuSubContent.displayName = DropdownMenuPrimitive.SubContent.displayNam
 
 const DropdownMenuContent = React.forwardRef<
   React.ElementRef<typeof DropdownMenuPrimitive.Content>,
-  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Content>
->(({ className, sideOffset = 4, ...props }, ref) => (
-  <DropdownMenuPrimitive.Portal>
-    <DropdownMenuPrimitive.Content
-      ref={ref}
-      sideOffset={sideOffset}
-      className={cn(
-        'bg-popover text-popover-foreground z-50 min-w-[8rem] overflow-hidden rounded-md border p-1 shadow-md',
-        'data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2',
-        className,
-      )}
-      {...props}
-    />
-  </DropdownMenuPrimitive.Portal>
-));
+  React.ComponentPropsWithoutRef<typeof DropdownMenuPrimitive.Content> & {
+    collisionPadding?: number | Partial<Record<'top' | 'right' | 'bottom' | 'left', number>>;
+  }
+>(({ className, sideOffset = 4, collisionPadding = 8, ...props }, ref) => {
+  if (typeof collisionPadding === 'number') {
+    if (collisionPadding < 0) {
+      throw new Error('collisionPadding must be a non-negative number');
+    }
+  } else if (typeof collisionPadding === 'object' && collisionPadding !== null) {
+    for (const key of Object.keys(collisionPadding)) {
+      if ((collisionPadding as any)[key] < 0) {
+        throw new Error(`collisionPadding.${key} must be a non-negative number`);
+      }
+    }
+  }
+
+  return (
+    <DropdownMenuPrimitive.Portal>
+      <DropdownMenuPrimitive.Content
+        ref={ref}
+        sideOffset={sideOffset}
+        collisionPadding={collisionPadding}
+        className={cn(
+          'bg-popover text-popover-foreground z-50 max-h-[var(--radix-dropdown-menu-content-available-height)] min-w-[8rem] overflow-hidden overflow-y-auto rounded-md border p-1 shadow-md',
+          'data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2',
+          className,
+        )}
+        {...props}
+      />
+    </DropdownMenuPrimitive.Portal>
+  );
+});
 DropdownMenuContent.displayName = DropdownMenuPrimitive.Content.displayName;
 
 const DropdownMenuItem = React.forwardRef<