refactor(exceptions): streamline exception constructors and enhance documentation

Author: dgarciasquare1

lib/src/exceptions/json_parse_exception.dart

@@ -8,6 +8,19 @@ import 'package:flutter_policy_engine/src/exceptions/i_policy_sdk_exceptions.dar
 /// the specific key that failed, the original error, and any additional
 /// validation errors.
 class JsonParseException implements IDetailPolicySDKException {
+  /// Creates a new JsonParseException.
+  ///
+  /// [message] should describe the parsing failure.
+  /// [key] optionally specifies which JSON key caused the failure.
+  /// [originalError] optionally provides the original parsing error.
+  /// [errors] optionally provides a map of field-specific validation errors.
+  JsonParseException(
+    this.message, {
+    this.key,
+    this.originalError,
+    this.errors,
+  });
+
   @override
   final String message;
 
@@ -23,19 +36,6 @@ class JsonParseException implements IDetailPolicySDKException {
   @override
   final Map<String, String>? errors;
 
-  /// Creates a new JsonParseException.
-  ///
-  /// [message] should describe the parsing failure.
-  /// [key] optionally specifies which JSON key caused the failure.
-  /// [originalError] optionally provides the original parsing error.
-  /// [errors] optionally provides a map of field-specific validation errors.
-  JsonParseException(
-    this.message, {
-    this.key,
-    this.originalError,
-    this.errors,
-  });
-
   @override
   String toString() {
     final buffer = StringBuffer('JsonParseException: $message');

lib/src/exceptions/json_serialize_exception.dart

@@ -7,6 +7,19 @@ import 'package:flutter_policy_engine/src/exceptions/i_policy_sdk_exceptions.dar
 /// occurs when policy objects contain non-serializable data types
 /// or circular references.
 class JsonSerializeException implements IDetailPolicySDKException {
+  /// Creates a new JsonSerializeException.
+  ///
+  /// [message] should describe the serialization failure.
+  /// [key] optionally specifies which object key caused the failure.
+  /// [originalError] optionally provides the original serialization error.
+  /// [errors] optionally provides a map of field-specific serialization errors.
+  JsonSerializeException(
+    this.message, {
+    this.key,
+    this.originalError,
+    this.errors,
+  });
+
   @override
   final String message;
 
@@ -22,19 +35,6 @@ class JsonSerializeException implements IDetailPolicySDKException {
   @override
   final Map<String, String>? errors;
 
-  /// Creates a new JsonSerializeException.
-  ///
-  /// [message] should describe the serialization failure.
-  /// [key] optionally specifies which object key caused the failure.
-  /// [originalError] optionally provides the original serialization error.
-  /// [errors] optionally provides a map of field-specific serialization errors.
-  JsonSerializeException(
-    this.message, {
-    this.key,
-    this.originalError,
-    this.errors,
-  });
-
   @override
   String toString() {
     final buffer = StringBuffer('JsonSerializeException: $message');

lib/src/exceptions/policy_not_initialized_exception.dart

@@ -15,13 +15,15 @@ import 'package:flutter_policy_engine/src/exceptions/i_policy_sdk_exceptions.dar
 /// }
 /// ```
 class PolicyNotInitializedException implements IPolicySDKException {
+  /// Creates a new [PolicyNotInitializedException] with the given [message].
+  const PolicyNotInitializedException(
+    this.message,
+  );
+
   /// A message describing the initialization error.
   @override
   final String message;
 
-  /// Creates a new [PolicyNotInitializedException] with the given [message].
-  const PolicyNotInitializedException(this.message);
-
   @override
   String toString() {
     final buffer = StringBuffer('PolicyNotInitializedException: $message');

lib/src/exceptions/policy_sdk_exception.dart

@@ -0,0 +1,22 @@
+import 'package:flutter_policy_engine/src/exceptions/i_policy_sdk_exceptions.dart';
+
+class PolicySDKException implements IPolicySDKException {
+  PolicySDKException(
+    this.message, {
+    required this.exception,
+  });
+
+  @override
+  final String message;
+
+  final Exception? exception;
+
+  @override
+  String toString() {
+    final buffer = StringBuffer('SDKException: $message');
+    if (exception != null) {
+      buffer.write('\nExtra info: ${exception?.toString()}');
+    }
+    return buffer.toString();
+  }
+}