♻️ refactor(discord-logger): centralize client ip retrieval

- introduce `getClientIp` method to centralize ip extraction logic
- ensure accurate client ip detection by robustly handling `x-forwarded-for`
- improve log consistency and maintainability for ip logging

src/shared/modules/discord-logger/discord-logger.service.ts

@@ -36,6 +36,23 @@ export class DiscordLoggerService {
     return clone;
   }
 
+  private getClientIp(req: Request): string {
+    // Get X-Forwarded-For header if present (from proxies/load balancers)
+    const xForwardedFor = req.headers['x-forwarded-for'];
+
+    if (xForwardedFor) {
+      // X-Forwarded-For can contain multiple IPs separated by commas
+      // Return only the first one (the original client IP)
+      const ips = Array.isArray(xForwardedFor)
+        ? xForwardedFor[0].split(',')
+        : xForwardedFor.split(',');
+      return ips[0]?.trim() || 'Unknown';
+    }
+
+    // Fallback to socket remote address
+    return req.socket?.remoteAddress || 'Unknown';
+  }
+
   logSuccess(
     req: Request,
     statusCode: number,
@@ -51,7 +68,7 @@ export class DiscordLoggerService {
       timestamp: new Date().toISOString(),
       method: req.method,
       path: req.originalUrl,
-      ip: req.headers['x-forwarded-for'] || req.socket?.remoteAddress,
+      ip: this.getClientIp(req),
       userAgent: req.headers['user-agent'],
       statusCode,
       response: this.sanitize(responseBody),
@@ -102,7 +119,7 @@ export class DiscordLoggerService {
       timestamp: new Date().toISOString(),
       method: req.method,
       path: req.originalUrl,
-      ip: req.headers['x-forwarded-for'] || req.socket?.remoteAddress,
+      ip: this.getClientIp(req),
       userAgent: req.headers['user-agent'],
       statusCode,
       error: errorData,