docs(exceptions): enhance PolicySDKException documentation

Author: dgarciasquare1

lib/src/exceptions/policy_sdk_exception.dart

@@ -1,16 +1,63 @@
 import 'package:flutter_policy_engine/src/exceptions/i_policy_sdk_exceptions.dart';
 
+/// A concrete implementation of [IPolicySDKException] that represents
+/// errors occurring within the Flutter Policy Engine SDK.
+///
+/// This exception class provides detailed error information including
+/// a descriptive message and an optional underlying exception that
+/// caused the error. It's used throughout the SDK to provide consistent
+/// error handling and reporting.
+///
+/// Example usage:
+/// ```dart
+/// try {
+///   // SDK operation that might fail
+/// } catch (e) {
+///   throw PolicySDKException(
+///     'Failed to load policy configuration',
+///     exception: e,
+///   );
+/// }
+/// ```
 class PolicySDKException implements IPolicySDKException {
+  /// Creates a new [PolicySDKException] with the specified error message
+  /// and optional underlying exception.
+  ///
+  /// The [message] should provide a clear, human-readable description
+  /// of what went wrong. The [exception] parameter can be used to
+  /// preserve the original exception that caused this error, which
+  /// is useful for debugging and error tracing.
+  ///
+  /// Parameters:
+  /// - [message]: A descriptive error message explaining what went wrong
+  /// - [exception]: An optional underlying exception that caused this error
   PolicySDKException(
     this.message, {
     required this.exception,
   });
 
+  /// A descriptive message explaining the error that occurred.
+  ///
+  /// This message should be clear enough for developers to understand
+  /// what went wrong and potentially how to fix it.
   @override
   final String message;
 
+  /// The underlying exception that caused this SDK error, if any.
+  ///
+  /// This field preserves the original exception for debugging purposes.
+  /// It can be null if the error was generated directly by the SDK
+  /// without an underlying exception.
   final Exception? exception;
 
+  /// Returns a string representation of this exception.
+  ///
+  /// The returned string includes the SDK exception message and,
+  /// if available, the underlying exception information for debugging.
+  ///
+  /// Returns:
+  /// A formatted string containing the error message and optional
+  /// underlying exception details.
   @override
   String toString() {
     final buffer = StringBuffer('SDKException: $message');