fix: normalize fileName property to handle case-insensitivity

The sendMedia endpoint had an inconsistency where:
- For images: only `filename` (lowercase) worked
- For documents/videos: only `fileName` (camelCase) worked

This was caused by the code only checking `data.fileName` without
considering that users might send `filename` (lowercase) in the
JSON payload.

This fix normalizes the property name at the beginning of the
mediaMessage method in all three channel services:
- whatsapp.baileys.service.ts
- evolution.channel.service.ts
- whatsapp.business.service.ts

Now both `fileName` and `filename` are accepted for all media types.

Closes #2459

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: enzowilliam

src/api/integrations/channel/evolution/evolution.channel.service.ts

@@ -597,7 +597,11 @@ export class EvolutionStartupService extends ChannelStartupService {
   }
 
   public async mediaMessage(data: SendMediaDto, file?: any, isIntegration = false) {
-    const mediaData: SendMediaDto = { ...data };
+    const mediaData: SendMediaDto = {
+      ...data,
+      // Normalize filename to fileName (handle case-insensitivity)
+      fileName: data.fileName || (data as any).filename,
+    };
 
     if (file) mediaData.media = file.buffer.toString('base64');
 

src/api/integrations/channel/meta/whatsapp.business.service.ts

@@ -1287,7 +1287,11 @@ export class BusinessStartupService extends ChannelStartupService {
   }
 
   public async mediaMessage(data: SendMediaDto, file?: any, isIntegration = false) {
-    const mediaData: SendMediaDto = { ...data };
+    const mediaData: SendMediaDto = {
+      ...data,
+      // Normalize filename to fileName (handle case-insensitivity)
+      fileName: data.fileName || (data as any).filename,
+    };
 
     if (file) mediaData.media = file.buffer.toString('base64');
 

src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts

@@ -2979,7 +2979,11 @@ export class BaileysStartupService extends ChannelStartupService {
   }
 
   public async mediaMessage(data: SendMediaDto, file?: any, isIntegration = false) {
-    const mediaData: SendMediaDto = { ...data };
+    const mediaData: SendMediaDto = {
+      ...data,
+      // Normalize filename to fileName (handle case-insensitivity)
+      fileName: data.fileName || (data as any).filename,
+    };
 
     if (file) mediaData.media = file.buffer.toString('base64');