Feat: Agregar botón para iniciar conversación con número nuevo

- Nuevo endpoint POST /api/messages/:instanceId/new-chat
- Valida que el número esté registrado en WhatsApp
- Crea el chat en la DB si no existe
- Modal en UI para ingresar número de teléfono
- Botón verde "+" junto a la barra de búsqueda

server/api/messages/[instanceId]/new-chat.post.ts

@@ -0,0 +1,138 @@
+/**
+ * POST /api/messages/:instanceId/new-chat
+ * Create or get a chat by phone number to start a new conversation
+ */
+import { query } from '../../../utils/database'
+import { baileysManager } from '../../../services/baileys/manager'
+import { randomUUID } from 'crypto'
+
+interface NewChatBody {
+  phoneNumber: string
+}
+
+export default defineEventHandler(async (event) => {
+  const username = getHeader(event, 'x-authentik-username')
+  if (!username) {
+    throw createError({ statusCode: 401, message: 'Unauthorized' })
+  }
+
+  const instanceId = getRouterParam(event, 'instanceId')
+  if (!instanceId) {
+    throw createError({ statusCode: 400, message: 'Missing instanceId' })
+  }
+
+  // Verify instance exists and is connected
+  const socket = baileysManager.getSocket(instanceId)
+  if (!socket) {
+    throw createError({ statusCode: 400, message: 'Instance not connected' })
+  }
+
+  const body = await readBody<NewChatBody>(event)
+
+  if (!body.phoneNumber?.trim()) {
+    throw createError({ statusCode: 400, message: 'Phone number is required' })
+  }
+
+  // Clean phone number: remove spaces, dashes, parentheses, and + prefix
+  const cleanNumber = body.phoneNumber.replace(/[\s\-\(\)\+]/g, '')
+
+  // Validate it's a numeric string
+  if (!/^\d+$/.test(cleanNumber)) {
+    throw createError({ statusCode: 400, message: 'Invalid phone number format' })
+  }
+
+  // Build WhatsApp JID (individual chat)
+  const jid = `${cleanNumber}@s.whatsapp.net`
+
+  try {
+    // Check if chat already exists
+    const existingChat = await query(
+      `SELECT id, jid, name, is_group, unread_count, last_message_at, last_message_type,
+              (SELECT COALESCE(content, caption) FROM messages m
+               WHERE m.chat_id = chats.id ORDER BY timestamp DESC LIMIT 1) as last_message
+       FROM chats
+       WHERE instance_id = $1 AND jid = $2`,
+      [instanceId, jid]
+    )
+
+    if (existingChat.rows.length > 0) {
+      // Chat exists, return it
+      const chat = existingChat.rows[0]
+      return {
+        success: true,
+        chat: {
+          id: chat.id,
+          jid: chat.jid,
+          name: chat.name || cleanNumber,
+          isGroup: chat.is_group,
+          unreadCount: chat.unread_count || 0,
+          lastMessage: chat.last_message,
+          lastMessageAt: chat.last_message_at,
+          lastMessageType: chat.last_message_type
+        },
+        isNew: false
+      }
+    }
+
+    // Chat doesn't exist, create it
+    const chatId = randomUUID()
+
+    // Try to get contact name from WhatsApp (optional, may fail)
+    let contactName = cleanNumber
+    try {
+      // Check if number exists on WhatsApp using onWhatsApp
+      const [exists] = await socket.onWhatsApp(jid)
+      if (!exists?.exists) {
+        throw createError({
+          statusCode: 400,
+          message: 'Este número no está registrado en WhatsApp'
+        })
+      }
+
+      // Try to get the push name or contact name
+      if (exists.notify) {
+        contactName = exists.notify
+      }
+    } catch (e: any) {
+      // If it's our validation error, rethrow
+      if (e.statusCode === 400) {
+        throw e
+      }
+      // Otherwise just use the number as name
+      console.log('[NewChat] Could not verify WhatsApp status:', e.message)
+    }
+
+    // Insert new chat
+    await query(
+      `INSERT INTO chats (id, instance_id, jid, name, is_group, unread_count, created_at, updated_at)
+       VALUES ($1, $2, $3, $4, false, 0, NOW(), NOW())`,
+      [chatId, instanceId, jid, contactName]
+    )
+
+    return {
+      success: true,
+      chat: {
+        id: chatId,
+        jid: jid,
+        name: contactName,
+        isGroup: false,
+        unreadCount: 0,
+        lastMessage: null,
+        lastMessageAt: null,
+        lastMessageType: null
+      },
+      isNew: true
+    }
+  } catch (e: any) {
+    // Rethrow HTTP errors
+    if (e.statusCode) {
+      throw e
+    }
+
+    console.error('[NewChat] Error creating chat:', e)
+    throw createError({
+      statusCode: 500,
+      message: `Error creating chat: ${e.message}`
+    })
+  }
+})