fix: token tracking pipeline + premium usage dashboard redesign

Backend fixes:
- Fix totalTokens defaulting to 0 when API omits totalTokenCount (now computes prompt+completion)
- Fix streaming metadata extraction: unwrap response wrapper in Anthropic/Gemini handlers
- Fix Zod schemas: handle SQL SUM(null) with nullable().transform()
- Add is_estimated column migration to token_usage table

Frontend redesign:
- Rewrite Usage page with area charts (nivo/line), horizontal bar model ranking
- StatCard: add trend indicators (% vs previous period) and inline SVG sparklines
- Premium color palette, prompt/completion ratio bar, top models mini-list
- Live indicator with 15s auto-refresh

Design system migration:
- Standardize all components on Gemini Nexus tokens (rounded-xl, border-white/[0.06])
- Refine UI components, proxy tabs, cloud account list, provider groups

src/components/ui/dropdown-menu.tsx

@@ -20,7 +20,7 @@ const DropdownMenuSubTrigger = React.forwardRef<
   <DropdownMenuPrimitive.SubTrigger
     ref={ref}
     className={cn(
-      'focus:bg-accent data-[state=open]:bg-accent flex cursor-default items-center rounded-sm px-2 py-1.5 text-sm outline-none select-none',
+      'flex cursor-default items-center rounded-md px-2 py-1.5 text-[13px] outline-none select-none transition-colors focus:bg-white/[0.06] data-[state=open]:bg-white/[0.06]',
       inset && 'pl-8',
       className,
     )}
@@ -39,7 +39,7 @@ const DropdownMenuSubContent = React.forwardRef<
   <DropdownMenuPrimitive.SubContent
     ref={ref}
     className={cn(
-      'bg-popover text-popover-foreground 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 z-50 min-w-[8rem] overflow-hidden rounded-md border p-1 shadow-lg',
+      'bg-popover text-popover-foreground 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 z-50 min-w-[8rem] overflow-hidden rounded-lg border border-white/[0.08] p-1 shadow-xl shadow-black/20',
       className,
     )}
     {...props}
@@ -72,7 +72,7 @@ const DropdownMenuContent = React.forwardRef<
         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',
+          '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-lg border border-white/[0.08] p-1 shadow-xl shadow-black/20',
           '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,
         )}
@@ -92,7 +92,7 @@ const DropdownMenuItem = React.forwardRef<
   <DropdownMenuPrimitive.Item
     ref={ref}
     className={cn(
-      'focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm px-2 py-1.5 text-sm transition-colors outline-none select-none data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
+      'relative flex cursor-default items-center rounded-md px-2 py-1.5 text-[13px] transition-colors outline-none select-none focus:bg-white/[0.06] focus:text-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
       inset && 'pl-8',
       className,
     )}
@@ -108,7 +108,7 @@ const DropdownMenuCheckboxItem = React.forwardRef<
   <DropdownMenuPrimitive.CheckboxItem
     ref={ref}
     className={cn(
-      'focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm py-1.5 pr-2 pl-8 text-sm transition-colors outline-none select-none data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
+      'relative flex cursor-default items-center rounded-md py-1.5 pr-2 pl-8 text-[13px] transition-colors outline-none select-none focus:bg-white/[0.06] focus:text-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
       className,
     )}
     checked={checked}
@@ -131,7 +131,7 @@ const DropdownMenuRadioItem = React.forwardRef<
   <DropdownMenuPrimitive.RadioItem
     ref={ref}
     className={cn(
-      'focus:bg-accent focus:text-accent-foreground relative flex cursor-default items-center rounded-sm py-1.5 pr-2 pl-8 text-sm transition-colors outline-none select-none data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
+      'relative flex cursor-default items-center rounded-md py-1.5 pr-2 pl-8 text-[13px] transition-colors outline-none select-none focus:bg-white/[0.06] focus:text-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50',
       className,
     )}
     {...props}
@@ -154,7 +154,7 @@ const DropdownMenuLabel = React.forwardRef<
 >(({ className, inset, ...props }, ref) => (
   <DropdownMenuPrimitive.Label
     ref={ref}
-    className={cn('px-2 py-1.5 text-sm font-semibold', inset && 'pl-8', className)}
+    className={cn('px-2 py-1.5 text-xs font-medium text-muted-foreground', inset && 'pl-8', className)}
     {...props}
   />
 ));
@@ -166,7 +166,7 @@ const DropdownMenuSeparator = React.forwardRef<
 >(({ className, ...props }, ref) => (
   <DropdownMenuPrimitive.Separator
     ref={ref}
-    className={cn('bg-muted -mx-1 my-1 h-px', className)}
+    className={cn('-mx-1 my-1 h-px bg-white/[0.06]', className)}
     {...props}
   />
 ));