feat: pre-registrant management and invitation system

Admin interface to review, filter, and batch-invite the 95 pre-registrants
from Baby Ghosts. Accept-invitation page pre-fills their data and collects
circle, pronouns, motivation, contribution tier, and agreement before
creating their member record.

server/api/invite/accept.post.js

@@ -0,0 +1,108 @@
+import jwt from 'jsonwebtoken'
+import PreRegistration from '../../models/preRegistration.js'
+import Member from '../../models/member.js'
+import { connectDB } from '../../utils/mongoose.js'
+
+export default defineEventHandler(async (event) => {
+  const body = await validateBody(event, inviteAcceptSchema)
+  const config = useRuntimeConfig(event)
+  await connectDB()
+
+  // Re-verify the token is still valid (not expired)
+  let decoded
+  try {
+    decoded = jwt.verify(body.token, config.jwtSecret)
+  } catch {
+    throw createError({ statusCode: 401, statusMessage: 'Invalid or expired invitation link' })
+  }
+
+  if (decoded.type !== 'prereg-invite' || decoded.preRegistrationId !== body.preRegistrationId) {
+    throw createError({ statusCode: 401, statusMessage: 'Invalid or expired invitation link' })
+  }
+
+  const preReg = await PreRegistration.findById(body.preRegistrationId)
+  if (!preReg) {
+    throw createError({ statusCode: 404, statusMessage: 'Pre-registration not found' })
+  }
+
+  if (preReg.status === 'accepted') {
+    throw createError({ statusCode: 400, statusMessage: 'This invitation has already been accepted' })
+  }
+
+  // Check no existing member with this email
+  const existingMember = await Member.findOne({ email: preReg.email })
+  if (existingMember) {
+    throw createError({ statusCode: 409, statusMessage: 'A member with this email already exists' })
+  }
+
+  // Create the member
+  const member = await Member.create({
+    email: preReg.email,
+    name: body.name,
+    pronouns: body.pronouns || undefined,
+    location: body.location || undefined,
+    circle: body.circle,
+    contributionTier: body.contributionTier,
+    bio: body.motivation || undefined,
+    status: body.contributionTier === '0' ? 'active' : 'pending_payment',
+  })
+
+  // Update pre-registration
+  await PreRegistration.findByIdAndUpdate(preReg._id, {
+    $set: {
+      status: 'accepted',
+      acceptedAt: new Date(),
+      memberId: member._id,
+    }
+  })
+
+  logActivity(member._id, 'member_joined', {
+    source: 'pre-registration',
+    preRegistrationId: preReg._id,
+  })
+
+  // For free tier, issue session and redirect to welcome
+  if (body.contributionTier === '0') {
+    const sessionToken = jwt.sign(
+      { memberId: member._id, email: member.email, tv: member.tokenVersion },
+      config.jwtSecret,
+      { expiresIn: '7d' },
+    )
+
+    setCookie(event, 'auth-token', sessionToken, {
+      httpOnly: true,
+      secure: process.env.NODE_ENV === 'production',
+      sameSite: 'lax',
+      path: '/',
+      maxAge: 60 * 60 * 24 * 7,
+    })
+
+    return {
+      success: true,
+      requiresPayment: false,
+      redirectUrl: '/welcome',
+      member: {
+        id: member._id,
+        email: member.email,
+        name: member.name,
+        circle: member.circle,
+        contributionTier: member.contributionTier,
+        status: member.status,
+      }
+    }
+  }
+
+  // For paid tiers, return member info so frontend can proceed to Helcim payment
+  return {
+    success: true,
+    requiresPayment: true,
+    member: {
+      id: member._id,
+      email: member.email,
+      name: member.name,
+      circle: member.circle,
+      contributionTier: member.contributionTier,
+      status: member.status,
+    }
+  }
+})