feat: wire up email sending for configurator submissions

- Created src/lib/email.ts with Nodemailer + Poste.io SMTP
- sendBriefToClient: formatted HTML brief email to the lead
- sendLeadNotification: admin notification with submission details
- Emails fire non-blocking (don't delay the brief response)
- Only sends if SMTP_HOST and SMTP_PASS are configured

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/app/(frontend)/api/configure/route.ts

@@ -1,4 +1,5 @@
 import { NextRequest, NextResponse } from 'next/server';
+import { sendBriefToClient, sendLeadNotification } from '@/lib/email';
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
@@ -206,6 +207,29 @@ export async function POST(request: NextRequest) {
     // Generate the brief
     const brief = generateMockBrief(body);
 
+    // Send emails (non-blocking — don't fail the response if email fails)
+    if (process.env.SMTP_HOST && process.env.SMTP_PASS) {
+      Promise.allSettled([
+        sendBriefToClient({
+          to: body.email,
+          name: body.name,
+          company: body.company,
+          brief,
+        }),
+        sendLeadNotification({
+          to: body.email,
+          name: body.name,
+          company: body.company,
+          brief,
+          services: body.services,
+          email: body.email,
+        }),
+      ]).catch(() => {
+        // Silently log — don't break the user flow
+        console.error('Email sending failed');
+      });
+    }
+
     return NextResponse.json({ success: true, brief });
   } catch {
     return NextResponse.json(