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

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

apps/web/src/app/api/dev/email-preview/route.ts

@@ -0,0 +1,47 @@
+import { NextRequest, NextResponse } from "next/server";
+import {
+  renderOtpEmail,
+  renderTeamInviteEmail,
+} from "~/server/email-templates";
+
+export async function GET(request: NextRequest) {
+  const { searchParams } = new URL(request.url);
+  const type = searchParams.get("type") || "otp";
+
+  if (process.env.NODE_ENV !== "development") {
+    return NextResponse.json({ error: "Not Found" }, { status: 404 });
+  }
+
+  try {
+    let html: string;
+
+    if (type === "otp") {
+      html = await renderOtpEmail({
+        otpCode: "ABC123",
+        loginUrl: "https://app.unsend.dev/login?token=abc123",
+        hostName: "Unsend",
+      });
+    } else if (type === "invite") {
+      html = await renderTeamInviteEmail({
+        teamName: "My Awesome Team",
+        inviteUrl: "https://app.unsend.dev/join-team?inviteId=123",
+        inviterName: "John Doe",
+        role: "admin",
+      });
+    } else {
+      return NextResponse.json({ error: "Invalid type" }, { status: 400 });
+    }
+
+    return new NextResponse(html, {
+      headers: {
+        "Content-Type": "text/html",
+      },
+    });
+  } catch (error) {
+    console.error("Error rendering email template:", error);
+    return NextResponse.json(
+      { error: "Failed to render email template" },
+      { status: 500 }
+    );
+  }
+}