feat: initialize NestJS application with global exception handling and request context

- Added nest-cli.json for Nest CLI configuration.
- Created package.json with dependencies and scripts for building, testing, and linting.
- Implemented AppController and AppService with a basic "Hello World!" response.
- Established AppModule with middleware for request ID and global interceptors for response standardization.
- Introduced ContextService for managing request-scoped context using AsyncLocalStorage.
- Developed custom decorators for response messages and standardized error handling with DTOs.
- Implemented global exception filter to handle various HTTP exceptions and Prisma errors.
- Added middleware for generating unique request IDs.
- Configured TypeScript settings for the project.
- Created comprehensive unit and e2e tests for the application.

src/common/exceptions/base.exception.ts

@@ -0,0 +1,67 @@
+/**
+ * src/common/exceptions/base.exception.ts
+ * * Defines a custom base exception class.
+ * * UPDATED: Now includes optional 'instruction' and 'details' fields.
+ */
+
+import { HttpException, HttpStatus } from '@nestjs/common';
+import { ErrorDetail } from '../dto/api-error-response.dto';
+
+/**
+ * A custom base exception that allows for a structured
+ * error response, including an application-specific error code.
+ *
+ * @example
+ * throw new BaseException(
+ * "Login failed, please verify OTP",
+ * HttpStatus.UNAUTHORIZED,
+ * "OTP_REQUIRED",
+ * [],
+ * "REQUIRE_OTP_VERIFICATION",
+ * { "needOtpVerification": true } // <-- New details field
+ * );
+ */
+export class BaseException extends HttpException {
+  public readonly code: string;
+  public readonly errors: ErrorDetail[];
+  public readonly instruction?: string; // <-- ADDED THIS
+  public readonly details?: unknown; // <-- CHANGED from any to unknown
+
+  /**
+   * @param message A high-level, human-readable summary of the error.
+   * @param status The HTTP status code.
+   * @param code An application-specific error code (e.g., "VALIDATION_ERROR").
+   * @param errors An optional array of detailed errors.
+   * @param instruction An optional frontend-specific action code.
+   * @param details An optional object with extra data for the frontend.
+   */
+  constructor(
+    message: string,
+    status: HttpStatus,
+    code: string,
+    errors?: ErrorDetail[],
+    instruction?: string, // <-- ADDED THIS
+    details?: unknown, // <-- CHANGED from any to unknown
+  ) {
+    // Call HttpException constructor with the message and status
+    super(
+      {
+        message,
+        code,
+        errors:
+          errors ||
+          (message ? [{ code, message: message, field: undefined }] : []),
+        instruction, // <-- ADDED THIS
+        details, // <-- ADDED THIS
+      },
+      status,
+    );
+
+    // Store custom properties
+    this.code = code;
+    this.errors =
+      errors || (message ? [{ code, message: message, field: undefined }] : []);
+    this.instruction = instruction; // <-- ADDED THIS
+    this.details = details; // <-- ADDED THIS
+  }
+}