feat: implement beautiful jsx-email templates for OTP and team invites (#196)

Co-authored-by: opencode <noreply@opencode.ai>

apps/web/src/server/email-templates/components/EmailHeader.tsx

@@ -0,0 +1,45 @@
+import React from "react";
+import { Container, Heading, Img } from "jsx-email";
+
+interface EmailHeaderProps {
+  logoUrl?: string;
+  title?: string;
+}
+
+export function EmailHeader({ logoUrl, title }: EmailHeaderProps) {
+  return (
+    <Container
+      style={{
+        padding: "20px 0",
+        textAlign: "left" as const,
+      }}
+    >
+      {logoUrl && (
+        <Img
+          src={logoUrl}
+          alt="Unsend"
+          style={{
+            width: "48px",
+            height: "48px",
+            margin: "0 0 16px 0",
+            display: "block",
+          }}
+        />
+      )}
+      {title && (
+        <Heading
+          style={{
+            fontSize: "24px",
+            fontWeight: "600",
+            color: "#111827",
+            margin: "0",
+            lineHeight: "1.3",
+            textAlign: "left" as const,
+          }}
+        >
+          {title}
+        </Heading>
+      )}
+    </Container>
+  );
+}