feat: add NewsletterPage and NewsletterContent components for newsletter subscription

app/newsletter/page.tsx

@@ -0,0 +1,5 @@
+import { NewsletterContent } from "@/components/newsletter-content";
+
+export default function NewsletterPage() {
+  return <NewsletterContent />;
+}

components/newsletter-content.tsx

@@ -0,0 +1,90 @@
+"use client";
+
+import { useState } from "react";
+import { Button, Card, Input, Label, Typography } from "poyraz-ui/atoms";
+
+export function NewsletterContent() {
+  const [name, setName] = useState("");
+  const [email, setEmail] = useState("");
+
+  const isValid = name.trim() && email.trim();
+
+  const handleSubmit = (event: React.FormEvent<HTMLFormElement>) => {
+    event.preventDefault();
+    if (!isValid) return;
+
+    const subject = encodeURIComponent(`Newsletter Subscription - ${name.trim()}`);
+    const body = encodeURIComponent(
+      `Hello,\n\nI want to subscribe to the weekly "Poyraz ile Yazilim" newsletter.\n\nName: ${name.trim()}\nEmail: ${email.trim()}`,
+    );
+
+    window.location.href = `mailto:poyrazavsever@gmail.com?subject=${subject}&body=${body}`;
+  };
+
+  return (
+    <section className="grid gap-3 md:grid-cols-[1fr_1.2fr]">
+      <Card className="rounded-sm border-border p-4">
+        <Typography variant="large" className="text-base">
+          Weekly Software Newsletter
+        </Typography>
+        <Typography variant="small" className="mt-1 text-muted-foreground">
+          Mail version of Poyraz ile Yazilim.
+        </Typography>
+
+        <div className="mt-4 space-y-3">
+          <div>
+            <Typography variant="small" className="text-muted-foreground">
+              Schedule
+            </Typography>
+            <Typography variant="small">Every Sunday</Typography>
+          </div>
+          <div>
+            <Typography variant="small" className="text-muted-foreground">
+              What you get
+            </Typography>
+            <Typography variant="small">Weekly software agenda and practical notes.</Typography>
+          </div>
+          <div>
+            <Typography variant="small" className="text-muted-foreground">
+              Delivery
+            </Typography>
+            <Typography variant="small">Directly to your inbox.</Typography>
+          </div>
+        </div>
+      </Card>
+
+      <Card className="rounded-sm border-border p-4">
+        <form onSubmit={handleSubmit} className="space-y-3">
+          <div className="space-y-1.5">
+            <Label htmlFor="newsletter-name">Name</Label>
+            <Input
+              id="newsletter-name"
+              value={name}
+              onChange={(event) => setName(event.target.value)}
+              placeholder="Your name"
+              className="rounded-sm"
+            />
+          </div>
+
+          <div className="space-y-1.5">
+            <Label htmlFor="newsletter-email">Email</Label>
+            <Input
+              id="newsletter-email"
+              type="email"
+              value={email}
+              onChange={(event) => setEmail(event.target.value)}
+              placeholder="you@example.com"
+              className="rounded-sm"
+            />
+          </div>
+
+          <div className="flex justify-end">
+            <Button type="submit" className="rounded-sm" disabled={!isValid}>
+              Subscribe
+            </Button>
+          </div>
+        </form>
+      </Card>
+    </section>
+  );
+}