feat: Enhance logging and type safety across various components and services

server.ts

@@ -80,6 +80,21 @@ const getDurationInMilliseconds = (start: [number, number]): number => {
     return (diff[0] * NS_PER_SEC + diff[1]) / NS_TO_MS;
 };
 
+/**
+ * Defines the structure for the detailed log object created for each request.
+ * This ensures type safety and consistency in our structured logs.
+ */
+interface RequestLogDetails {
+  user_id?: string;
+  method: string;
+  originalUrl: string;
+  statusCode: number;
+  statusMessage: string;
+  duration: string;
+  // The 'req' property is added conditionally for client/server errors.
+  req?: { headers: express.Request['headers']; body: express.Request['body'] };
+}
+
 const requestLogger = (req: Request, res: Response, next: NextFunction) => {
     const requestId = randomUUID();
     const user = req.user as UserProfile | undefined;
@@ -102,7 +117,7 @@ const requestLogger = (req: Request, res: Response, next: NextFunction) => {
         const finalUser = req.user as UserProfile | undefined;
 
         // The base log object includes details relevant for all status codes.
-        const logDetails: Record<string, any> = {
+        const logDetails: RequestLogDetails = {
             user_id: finalUser?.user_id,
             method,
             originalUrl,