docs: update documentation for v0.4.0 release

- Update README.md with v0.4.0 features and screenshots placeholders
- Update architecture.md with v0.4.0 implementation status
- Update progress.md marking all 27 tasks as completed
- Create CHANGELOG.md with complete release notes
- Add v0.4.0 frontend components and hooks

frontend/src/components/ui/badge.tsx

@@ -1,26 +1,7 @@
 import * as React from "react"
-import { cva, type VariantProps } from "class-variance-authority"
+import type { VariantProps } from "class-variance-authority"
 import { cn } from "@/lib/utils"
-
-const badgeVariants = cva(
-  "inline-flex items-center rounded-full border px-2.5 py-0.5 text-xs font-semibold transition-colors focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2",
-  {
-    variants: {
-      variant: {
-        default:
-          "border-transparent bg-primary text-primary-foreground hover:bg-primary/80",
-        secondary:
-          "border-transparent bg-secondary text-secondary-foreground hover:bg-secondary/80",
-        destructive:
-          "border-transparent bg-destructive text-destructive-foreground hover:bg-destructive/80",
-        outline: "text-foreground",
-      },
-    },
-    defaultVariants: {
-      variant: "default",
-    },
-  }
-)
+import { badgeVariants } from "./badge-variants"
 
 export interface BadgeProps
   extends React.HTMLAttributes<HTMLDivElement>,
@@ -32,4 +13,4 @@ function Badge({ className, variant, ...props }: BadgeProps) {
   )
 }
 
-export { Badge, badgeVariants }
+export { Badge }