feat: Add comprehensive backend validation, toast notifications, and Tokyo Night theme

- Backend: Add server-side validation with go-playground/validator/v10
- Frontend: Add toast notifications for API errors with @zerodevx/svelte-toast
- UI: Complete Tokyo Night theme redesign with modern animations
- Docs: Update COMPLETE_DOCUMENTATION.md and README.md with all enhancements
- Validation: Email format, password strength, and input sanitization
- UX: Real-time error feedback, loading states, and responsive design

frontend/package.json

@@ -0,0 +1,33 @@
+{
+	"name": "frontend",
+	"private": true,
+	"version": "0.0.1",
+	"type": "module",
+	"scripts": {
+		"dev": "vite dev",
+		"build": "vite build",
+		"preview": "vite preview",
+		"prepare": "svelte-kit sync || echo ''",
+		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
+		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch"
+	},
+	"devDependencies": {
+		"@sveltejs/adapter-static": "^3.0.1",
+		"@sveltejs/kit": "^2.49.1",
+		"@sveltejs/vite-plugin-svelte": "^6.2.1",
+		"@tailwindcss/postcss": "^4.1.18",
+		"@tailwindcss/typography": "^0.5.19",
+		"autoprefixer": "^10.4.23",
+		"postcss": "^8.5.6",
+		"svelte": "^5.45.6",
+		"svelte-check": "^4.3.4",
+		"tailwindcss": "^4.1.18",
+		"typescript": "^5.9.3",
+		"vite": "^7.2.6"
+	},
+	"dependencies": {
+		"@zerodevx/svelte-toast": "^0.9.6",
+		"sveltekit-superforms": "^2.29.1",
+		"zod": "^4.3.5"
+	}
+}