feat(frontend): add Front/ — Vite/React frontend with backend pipeline integration

Mirror of design_agent_front/design-agent/ for shipping alongside backend.

Vite plugin (vitePluginPhaseZApi) endpoints :
  - POST /api/run   — spawn `python -m src.phase_z2_pipeline` with overrides
  - GET  /api/sample-mdx?mdx=03/04/05 — fixed sample MDX
  - GET  /frame-preview/{n} — figma preview thumbnails
  - GET  /data/runs/{run_id}/{path} — pipeline artifacts (final.html, step*.json, ...)

Env toggle forward (보고용) :
  PHASE_Z_ALLOW_RESTRUCTURE / PHASE_Z_ALLOW_REJECT / PHASE_Z_MAX_RANK=32

Components :
  - LeftMdxPanel (03/04/05 fix list + section tree)
  - SlideCanvas (iframe + slideOverrideCss prop for inline CSS inject)
  - FramePanel (label priority + confidence sort)
  - LayoutPanel

README with mermaid diagrams covering the 5-step demo flow.
node_modules / dist / .manus-logs / .env excluded via .gitignore.

Front/client/src/components/ui/badge.tsx

@@ -0,0 +1,46 @@
+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";
+
+const badgeVariants = cva(
+  "inline-flex items-center justify-center rounded-md border px-2 py-0.5 text-xs font-medium w-fit whitespace-nowrap shrink-0 [&>svg]:size-3 gap-1 [&>svg]:pointer-events-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 transition-[color,box-shadow] overflow-hidden",
+  {
+    variants: {
+      variant: {
+        default:
+          "border-transparent bg-primary text-primary-foreground [a&]:hover:bg-primary/90",
+        secondary:
+          "border-transparent bg-secondary text-secondary-foreground [a&]:hover:bg-secondary/90",
+        destructive:
+          "border-transparent bg-destructive text-white [a&]:hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 dark:bg-destructive/60",
+        outline:
+          "text-foreground [a&]:hover:bg-accent [a&]:hover:text-accent-foreground",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+);
+
+function Badge({
+  className,
+  variant,
+  asChild = false,
+  ...props
+}: React.ComponentProps<"span"> &
+  VariantProps<typeof badgeVariants> & { asChild?: boolean }) {
+  const Comp = asChild ? Slot : "span";
+
+  return (
+    <Comp
+      data-slot="badge"
+      className={cn(badgeVariants({ variant }), className)}
+      {...props}
+    />
+  );
+}
+
+export { Badge, badgeVariants };