feat: add frontend source code

Add search-zen-50 React SPA source code to frontend/ directory.
Build artifacts (dist, node_modules, lock files) are gitignored.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/tailwind.config.ts

@@ -0,0 +1,60 @@
+import type { Config } from "tailwindcss";
+
+export default {
+  darkMode: ["class"],
+  content: ["./pages/**/*.{ts,tsx}", "./components/**/*.{ts,tsx}", "./app/**/*.{ts,tsx}", "./src/**/*.{ts,tsx}"],
+  prefix: "",
+  theme: {
+    container: {
+      center: true,
+      padding: "2rem",
+      screens: { "2xl": "1400px" },
+    },
+    extend: {
+      fontFamily: {
+        sans: ['Inter', 'system-ui', 'sans-serif'],
+        mono: ['IBM Plex Mono', 'monospace'],
+      },
+      colors: {
+        border: "hsl(var(--border))",
+        input: "hsl(var(--input))",
+        ring: "hsl(var(--ring))",
+        background: "hsl(var(--background))",
+        foreground: "hsl(var(--foreground))",
+        primary: { DEFAULT: "hsl(var(--primary))", foreground: "hsl(var(--primary-foreground))" },
+        secondary: { DEFAULT: "hsl(var(--secondary))", foreground: "hsl(var(--secondary-foreground))" },
+        destructive: { DEFAULT: "hsl(var(--destructive))", foreground: "hsl(var(--destructive-foreground))" },
+        muted: { DEFAULT: "hsl(var(--muted))", foreground: "hsl(var(--muted-foreground))" },
+        accent: { DEFAULT: "hsl(var(--accent))", foreground: "hsl(var(--accent-foreground))" },
+        popover: { DEFAULT: "hsl(var(--popover))", foreground: "hsl(var(--popover-foreground))" },
+        card: { DEFAULT: "hsl(var(--card))", foreground: "hsl(var(--card-foreground))" },
+        link: { DEFAULT: "hsl(var(--link))", hover: "hsl(var(--link-hover))" },
+        "result-hover": "hsl(var(--result-hover))",
+        sidebar: {
+          DEFAULT: "hsl(var(--sidebar-background))",
+          foreground: "hsl(var(--sidebar-foreground))",
+          primary: "hsl(var(--sidebar-primary))",
+          "primary-foreground": "hsl(var(--sidebar-primary-foreground))",
+          accent: "hsl(var(--sidebar-accent))",
+          "accent-foreground": "hsl(var(--sidebar-accent-foreground))",
+          border: "hsl(var(--sidebar-border))",
+          ring: "hsl(var(--sidebar-ring))",
+        },
+      },
+      borderRadius: {
+        lg: "var(--radius)",
+        md: "calc(var(--radius) - 2px)",
+        sm: "calc(var(--radius) - 4px)",
+      },
+      keyframes: {
+        "accordion-down": { from: { height: "0" }, to: { height: "var(--radix-accordion-content-height)" } },
+        "accordion-up": { from: { height: "var(--radix-accordion-content-height)" }, to: { height: "0" } },
+      },
+      animation: {
+        "accordion-down": "accordion-down 0.2s ease-out",
+        "accordion-up": "accordion-up 0.2s ease-out",
+      },
+    },
+  },
+  plugins: [require("tailwindcss-animate")],
+} satisfies Config;