refactor(helcim): wrapped PATCH body, first-activation welcome email guard

Moves updateHelcimSubscription to the live-verified wrapped shape
(PATCH /subscriptions { subscriptions: [{ id, ...payload }] }), adds a prior-
status check so sendWelcomeEmail only fires on pending_payment to active
transitions, short-circuits get-or-create-customer when a valid
helcimCustomerId is already on file, and replaces member.save() Slack-status
writes with findByIdAndUpdate({ runValidators: false }) to avoid save-time
validator pitfalls.

server/api/helcim/get-or-create-customer.post.js

@@ -1,17 +1,47 @@
 // Get existing or create new Helcim customer (for upgrading members)
+import Member from '../../models/member.js'
 import { requireAuth } from '../../utils/auth.js'
-import { findHelcimCustomerByEmail, createHelcimCustomer } from '../../utils/helcim.js'
+import {
+  getHelcimCustomer,
+  findHelcimCustomerByEmail,
+  createHelcimCustomer
+} from '../../utils/helcim.js'
 
 export default defineEventHandler(async (event) => {
   try {
     const member = await requireAuth(event)
 
-    // First, try to find an existing customer
+    // 1. Short-circuit: member already has a Helcim customer ID on file.
+    //    Verify it still resolves before falling through — otherwise we'd
+    //    silently orphan the old customer and create a duplicate.
+    if (member.helcimCustomerId) {
+      try {
+        const customer = await getHelcimCustomer(member.helcimCustomerId)
+        if (customer?.id) {
+          return {
+            success: true,
+            customerId: customer.id,
+            customerCode: customer.customerCode,
+            existing: true
+          }
+        }
+      } catch (err) {
+        // Only fall through on 404 (customer was deleted in Helcim).
+        // Any other error must propagate — silently recreating was the
+        // original duplicate-customer bug.
+        if (err?.statusCode !== 404) throw err
+      }
+    }
+
+    // 2. Fall back to search by email (case-insensitive match).
     let existingCustomer = null
     try {
       const searchData = await findHelcimCustomerByEmail(member.email)
-      if (searchData.customers && searchData.customers.length > 0) {
-        existingCustomer = searchData.customers.find(c => c.email === member.email) || null
+      const memberEmail = member.email.toLowerCase()
+      if (searchData.customers?.length) {
+        existingCustomer = searchData.customers.find(
+          c => c.email?.toLowerCase() === memberEmail
+        ) || null
       }
     } catch (searchError) {
       console.error('Error searching for customer:', searchError)
@@ -20,8 +50,11 @@ export default defineEventHandler(async (event) => {
 
     if (existingCustomer) {
       if (!member.helcimCustomerId) {
-        member.helcimCustomerId = existingCustomer.id
-        await member.save()
+        await Member.findByIdAndUpdate(
+          member._id,
+          { $set: { helcimCustomerId: existingCustomer.id } },
+          { runValidators: false }
+        )
       }
       return {
         success: true,
@@ -31,15 +64,18 @@ export default defineEventHandler(async (event) => {
       }
     }
 
-    // No existing customer found — create one
+    // 3. No match anywhere — create a fresh customer.
     const customerData = await createHelcimCustomer({
       contactName: member.name,
       businessName: member.name,
       email: member.email
     })
 
-    member.helcimCustomerId = customerData.id
-    await member.save()
+    await Member.findByIdAndUpdate(
+      member._id,
+      { $set: { helcimCustomerId: customerData.id } },
+      { runValidators: false }
+    )
 
     return {
       success: true,