feat(bookings): implement booking system and confirmation flow

Add database tables and repository for managing bookings
Create API endpoints for booking submission and capacity management
Update landing page to persist bookings before WhatsApp redirection

server/utils/user-repository.ts

@@ -256,6 +256,36 @@ export async function listPublicContacts(): Promise<PublicContact[]> {
   }))
 }
 
+export async function getPublicContactById(contactId: string): Promise<PublicContact | null> {
+  await ensureDatabaseReady()
+  const sql = getSqlClient()
+
+  const [row] = await sql<Pick<DbUserRow, 'id' | 'full_name' | 'phone_number' | 'role'>[]>`
+    select
+      users.id,
+      users.full_name,
+      users.phone_number,
+      users.role
+    from users
+    where users.id = ${contactId}
+      and users.is_active = true
+      and users.phone_number is not null
+      and users.phone_number <> ''
+    limit 1
+  `
+
+  if (!row) {
+    return null
+  }
+
+  return {
+    id: row.id,
+    fullName: row.full_name,
+    phoneNumber: row.phone_number || '',
+    role: row.role
+  }
+}
+
 export async function createUser(input: {
   username: string
   fullName: string