feat: Complete multi-blog setup with 12 collections and subdomain routing

- Added 12 blog collections: art, bfs, dfs, problems, puzzles, reviews, reflections, vibes, workflows, magic, contests, poetry
- Created content config with glob loaders for all collections
- Added sample posts for each collection
- Fixed TypeScript collection recognition by removing duplicate config
- Made BlogPosts component collection-aware for proper routing
- Created individual post pages ([...slug].astro) for each collection
- Added Netlify subdomain routing configuration
- Updated all references to use neeldhara.blog as main domain
- Fixed navigation links in all-blogs component

Ready for GitHub/Netlify deployment with subdomain support.

src/pages/404.astro

@@ -0,0 +1,34 @@
+---
+import { Button } from "@/components/ui/button";
+import DefaultLayout from "@/layouts/DefaultLayout.astro";
+import { ArrowLeft } from "lucide-react";
+---
+
+<DefaultLayout title="404: Not Found" description="Sorry, the page you're looking for doesn't exist.">
+  <div class="container mt-12 flex justify-center py-28 text-center lg:mt-20  lg:py-32">
+    <div class="relative z-10 max-w-2xl">
+      <h1 class="from-foreground to-foreground/70 relative mb-6 bg-linear-to-br bg-clip-text py-2 text-5xl font-bold text-transparent sm:text-6xl lg:text-7xl">
+        Page Not Found
+      </h1>
+
+      <p class="text-muted-foreground mb-10 text-xl">
+        {`Sorry, we couldn't find the page you're looking for. The page might have been removed or the URL might be
+        incorrect.`}
+      </p>
+
+      <div class="flex flex-col items-center gap-4 sm:flex-row sm:justify-center">
+        <a href="/">
+          <Button  size="lg" className="group min-w-[200px] gap-2">
+            <ArrowLeft className="size-5 transition-transform group-hover:-translate-x-1" />
+            Back to Home
+          </Button>
+        </a>
+        <a href="/contact">
+          <Button asChild variant="outline" size="lg" className="min-w-[200px]">
+            Contact Support
+          </Button>
+        </a>
+      </div>
+    </div>
+  </div>
+</DefaultLayout>