feat: SMTP config en DB, historial mensajes, JWT 90d, email OTP con Prisma

- schema.prisma: modelo message_logs (channel, recipient, body, status, error)
- email-otp.service.ts: lee config SMTP desde DB (settings.smtp_config), registra log en message_logs
- sms.service.ts: registra log en message_logs tras cada envío (éxito y error)
- auth.module.ts: agrega PrismaModule, JWT expira en 90d
- settings.controller.ts: GET/PATCH /settings/smtp + GET /settings/message-logs
- settings.service.ts: método getMessageLogs con paginación y filtro por canal
- settings.module.ts: importa AuthModule + EmailOtpService

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/settings/settings.controller.ts

@@ -1,13 +1,14 @@
-import { Controller, Get, Patch, Body, UseGuards, Param, Res } from '@nestjs/common';
+import { Controller, Get, Patch, Body, UseGuards, Param, Res, Query } from '@nestjs/common';
 import { ApiTags, ApiBearerAuth } from '@nestjs/swagger';
 import { Response } from 'express';
 import { SettingsService } from './settings.service';
 import { JwtAuthGuard } from '../auth/jwt-auth.guard';
+import { EmailOtpService } from '../auth/email-otp.service';
 
 @ApiTags('Settings')
 @Controller('settings')
 export class SettingsController {
-  constructor(private settings: SettingsService) {}
+  constructor(private settings: SettingsService, private emailOtp: EmailOtpService) {}
 
   @Get()
   getGlobal() { return this.settings.getGlobal(); }
@@ -29,6 +30,27 @@ export class SettingsController {
     return this.settings.updatePolicy(key, body.content);
   }
 
+  // SMTP config
+  @Get('smtp')
+  @UseGuards(JwtAuthGuard) @ApiBearerAuth()
+  async getSmtp() {
+    const cfg = await this.emailOtp.getSmtpConfig();
+    return cfg ?? {};
+  }
+
+  @Patch('smtp')
+  @UseGuards(JwtAuthGuard) @ApiBearerAuth()
+  saveSmtp(@Body() body: { host: string; port: string; user: string; pass: string; from?: string }) {
+    return this.emailOtp.saveSmtpConfig(body);
+  }
+
+  // Message logs
+  @Get('message-logs')
+  @UseGuards(JwtAuthGuard) @ApiBearerAuth()
+  getMessageLogs(@Query('page') page = '1', @Query('limit') limit = '50', @Query('channel') channel?: string) {
+    return this.settings.getMessageLogs(+page, +limit, channel);
+  }
+
   // Maps key
   @Get('maps-key')
   async getMapsKey() {