Refactor email templates to use plain text format and update sender addresses

- Simplified the magic link email format to plain text for better compatibility.
- Updated the welcome email to use plain text and changed the sender address to match the domain.
- Enhanced event registration email format to plain text, removing HTML styling for a cleaner approach.

server/api/auth/login.post.js

@@ -9,7 +9,6 @@ import { emailSchema } from "../../utils/schemas.js";
 const resend = new Resend(process.env.RESEND_API_KEY);
 
 export default defineEventHandler(async (event) => {
-  // Connect to database
   await connectDB();
 
   const { email } = await validateBody(event, emailSchema);
@@ -19,14 +18,12 @@ export default defineEventHandler(async (event) => {
   const member = await Member.findOne({ email });
 
   if (!member) {
-    // Return same response shape to prevent enumeration
     return {
       success: true,
       message: GENERIC_MESSAGE,
     };
   }
 
-  // Generate magic link token (use runtime config for consistency with verify/requireAuth)
   const config = useRuntimeConfig(event);
   const token = jwt.sign(
     { memberId: member._id },
@@ -34,33 +31,22 @@ export default defineEventHandler(async (event) => {
     { expiresIn: "15m" },
   );
 
-  // Get the base URL for the magic link
   const headers = getHeaders(event);
   const baseUrl =
     process.env.BASE_URL ||
     `${headers.host?.includes("localhost") ? "http" : "https"}://${headers.host}`;
 
-  // Send magic link via Resend
   try {
     await resend.emails.send({
       from: "Ghost Guild <ghostguild@babyghosts.org>",
       to: email,
       subject: "Your Ghost Guild login link",
-      html: `
-        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
-          <h2 style="color: #2563eb;">Welcome back to Ghost Guild!</h2>
-          <p>Click the button below to sign in to your account:</p>
-          <div style="text-align: center; margin: 30px 0;">
-            <a href="${baseUrl}/api/auth/verify?token=${token}"
-               style="background-color: #2563eb; color: white; padding: 12px 24px; text-decoration: none; border-radius: 6px; display: inline-block;">
-              Sign In to Ghost Guild
-            </a>
-          </div>
-          <p style="color: #666; font-size: 14px;">
-            This link will expire in 15 minutes for security. If you didn't request this login link, you can safely ignore this email.
-          </p>
-        </div>
-      `,
+      text: `Hi,
+
+Sign in to Ghost Guild:
+${baseUrl}/api/auth/verify?token=${token}
+
+This link expires in 15 minutes. If you didn't request it, ignore this email.`,
     });
 
     return {