feat: polish invoice editor and viewer UI with custom NumberInput

component

- Create custom NumberInput component with increment/decrement buttons
- Add 0.25 step increments for hours and rates in invoice forms
- Implement emerald-themed styling with hover states and accessibility
- Add keyboard navigation (arrow keys) and proper ARIA support
- Condense invoice editor tax/totals section into efficient grid layout
- Update client dropdown to single-line format (name + email)
- Add fixed footer with floating action bar pattern matching business
  forms
- Redesign invoice viewer with better space utilization and visual
  hierarchy
- Maintain professional appearance and consistent design system
- Fix Next.js 15 params Promise handling across all invoice pages
- Resolve TypeScript compilation errors and type-only imports

src/components/ui/button.tsx

@@ -1,8 +1,8 @@
-import * as React from "react"
-import { Slot } from "@radix-ui/react-slot"
-import { cva, type VariantProps } from "class-variance-authority"
+import * as React from "react";
+import { Slot } from "@radix-ui/react-slot";
+import { cva, type VariantProps } from "class-variance-authority";
 
-import { cn } from "~/lib/utils"
+import { cn } from "~/lib/utils";
 
 const buttonVariants = cva(
   "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-all disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg:not([class*='size-'])]:size-4 shrink-0 [&_svg]:shrink-0 outline-none focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-[3px] aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive",
@@ -11,10 +11,12 @@ const buttonVariants = cva(
       variant: {
         default:
           "bg-primary text-primary-foreground shadow-xs hover:bg-primary/90",
+        brand:
+          "bg-brand-gradient text-white shadow-lg hover:bg-brand-gradient hover:shadow-xl font-medium",
         destructive:
           "bg-destructive text-white shadow-xs hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 dark:bg-destructive/60",
         outline:
-          "border bg-background shadow-xs hover:bg-accent hover:text-accent-foreground dark:bg-input/30 dark:border-input dark:hover:bg-input/50",
+          "border border-border/40 bg-background/60 shadow-sm backdrop-blur-sm hover:bg-accent/50 hover:text-accent-foreground hover:border-border/60 transition-all duration-200",
         secondary:
           "bg-secondary text-secondary-foreground shadow-xs hover:bg-secondary/80",
         ghost:
@@ -32,8 +34,8 @@ const buttonVariants = cva(
       variant: "default",
       size: "default",
     },
-  }
-)
+  },
+);
 
 function Button({
   className,
@@ -43,9 +45,9 @@ function Button({
   ...props
 }: React.ComponentProps<"button"> &
   VariantProps<typeof buttonVariants> & {
-    asChild?: boolean
+    asChild?: boolean;
   }) {
-  const Comp = asChild ? Slot : "button"
+  const Comp = asChild ? Slot : "button";
 
   return (
     <Comp
@@ -53,7 +55,7 @@ function Button({
       className={cn(buttonVariants({ variant, size, className }))}
       {...props}
     />
-  )
+  );
 }
 
-export { Button, buttonVariants }
+export { Button, buttonVariants };