feat: initial tools service with document scanner, image & PDF tools

Self-hosted document scanner and media processing tools.
- Rust Axum gateway + worker pool with NATS JetStream
- Next.js 16 frontend with shadcn/ui
- Scanner pipeline: edge detection, warp, binarization, OCR
- Image tools: compress, resize, convert
- PDF tools: merge, split, compress
- CI/CD with Docker multi-stage build

Co-Authored-By: Kilo <kilo@kilo.ai>

frontend/src/app/page.tsx

@@ -0,0 +1,58 @@
+import { ToolGrid } from "@/components/tools/tool-grid";
+
+export default function HomePage() {
+  return (
+    <div className="container mx-auto px-4 py-12">
+      {/* Hero */}
+      <section className="text-center mb-16">
+        <h1 className="text-4xl md:text-5xl font-bold mb-4">
+          <span className="gradient-text">Tools</span>
+        </h1>
+        <p className="text-lg text-muted-foreground max-w-2xl mx-auto">
+          Self-hosted document scanner, image tools & PDF tools.
+          <br />
+          Semua proses di backend — cepat, hemat,{" "}
+          <span className="text-primary font-semibold">privacy first</span>.
+        </p>
+        <div className="flex items-center justify-center gap-4 mt-6 text-sm text-muted-foreground">
+          <span className="flex items-center gap-1">
+            <span className="w-2 h-2 rounded-full bg-green-500" />
+            Rust + WASM
+          </span>
+          <span className="flex items-center gap-1">
+            <span className="w-2 h-2 rounded-full bg-primary" />
+            No upload to 3rd party
+          </span>
+          <span className="flex items-center gap-1">
+            <span className="w-2 h-2 rounded-full bg-amber-500" />
+            Auto-delete 1 jam
+          </span>
+        </div>
+      </section>
+
+      {/* Tools Grid */}
+      <section>
+        <div className="flex items-center justify-between mb-8">
+          <h2 className="text-2xl font-bold">All Tools</h2>
+          <span className="text-sm text-muted-foreground font-mono">
+            14 tools
+          </span>
+        </div>
+        <ToolGrid />
+      </section>
+
+      {/* Privacy Note */}
+      <section className="mt-16 p-6 rounded-xl border glass text-center">
+        <h2 className="text-lg font-semibold mb-2">🔒 Privacy First</h2>
+        <p className="text-sm text-muted-foreground max-w-xl mx-auto">
+          Semua file diproses di server kami dan{" "}
+          <span className="text-primary font-medium">
+            otomatis dihapus setelah 1 jam
+          </span>
+          . Tidak ada data yang dikirim ke pihak ketiga. Source code
+          open-source di GitHub.
+        </p>
+      </section>
+    </div>
+  );
+}