feat(responsive,seo): implement responsive design and SEO optimizations

Phase 4: Responsive Design Optimizations
- Increase touch target sizes to min 44px for mobile
- Add touch-manipulation for better touch handling
- Optimize button and input sizes for mobile devices
- Implement responsive font sizing (16px -> 17px -> 18px)

Phase 5: SEO Optimizations
- Enhance metadata with comprehensive Open Graph tags
- Add Twitter Card metadata with images
- Implement Google Search Console verification
- Add structured data (Organization, Website schemas)
- Improve keywords and descriptions

Files modified:
- src/components/ui/button.tsx: Touch-friendly sizes
- src/components/ui/input.tsx: Mobile-optimized inputs
- src/app/globals.css: Responsive font sizing
- src/app/layout.tsx: Enhanced metadata and structured data
- src/components/seo/structured-data.tsx: New structured data components

Impact:
- Better mobile user experience
- Improved search engine visibility
- Enhanced social media sharing
- WCAG 2.1 touch target compliance
- Better SEO performance

src/components/ui/button.tsx

@@ -5,7 +5,7 @@ import { cva, type VariantProps } from "class-variance-authority"
 import { cn } from "@/lib/utils"
 
 const buttonVariants = cva(
-  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-lg text-sm font-medium transition-all duration-200 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:ring-2 focus-visible:ring-[#1C1C1C] focus-visible:ring-offset-2 focus-visible:ring-offset-white",
+  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-lg text-sm font-medium transition-all duration-200 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:ring-2 focus-visible:ring-[#1C1C1C] focus-visible:ring-offset-2 focus-visible:ring-offset-white min-h-[44px] min-w-[44px] touch-manipulation",
   {
     variants: {
       variant: {
@@ -23,10 +23,10 @@ const buttonVariants = cva(
           "text-[#1C1C1C] underline-offset-4 hover:underline hover:text-[#C41E3A]",
       },
       size: {
-        default: "h-10 px-4 py-2",
-        sm: "h-8 rounded-md px-3 text-xs",
+        default: "h-11 px-4 py-2",
+        sm: "h-9 rounded-md px-3 text-xs",
         lg: "h-12 rounded-lg px-6 text-base",
-        icon: "h-10 w-10",
+        icon: "h-11 w-11",
       },
     },
     defaultVariants: {

src/components/ui/input.tsx

@@ -28,7 +28,7 @@ const Input = React.forwardRef<HTMLInputElement, InputProps>(
           id={inputId}
           data-slot="input"
           className={cn(
-            "file:text-foreground placeholder:text-[#8C8C8C] selection:bg-[#1C1C1C] selection:text-white h-10 w-full min-w-0 rounded-lg border border-[#E5E5E5] bg-[#FAFAFA] px-4 py-2 text-base text-[#1C1C1C] shadow-sm transition-all duration-300 outline-none file:inline-flex file:h-7 file:border-0 file:bg-transparent file:text-sm file:font-medium disabled:pointer-events-none disabled:cursor-not-allowed disabled:opacity-50 md:text-sm",
+            "file:text-foreground placeholder:text-[#8C8C8C] selection:bg-[#1C1C1C] selection:text-white h-12 w-full min-w-0 rounded-lg border border-[#E5E5E5] bg-[#FAFAFA] px-4 py-3 text-base text-[#1C1C1C] shadow-sm transition-all duration-300 outline-none file:inline-flex file:h-7 file:border-0 file:bg-transparent file:text-sm file:font-medium disabled:pointer-events-none disabled:cursor-not-allowed disabled:opacity-50 min-h-[44px] touch-manipulation",
             "focus-visible:border-[#1C1C1C] focus-visible:ring-2 focus-visible:ring-[#1C1C1C]/50 focus-visible:shadow-lg focus-visible:shadow-[#1C1C1C]/20",
             "hover:border-[#3D3D3D]",
             error && "border-[#C41E3A] focus-visible:border-[#C41E3A] focus-visible:ring-[#C41E3A]/50",