refactor(dart): merge all runtime exceptions into single fory_exception.dart (#3436)

## Why?

The current Dart exception hierarchy spreads runtime exceptions across
four separate files under `dart/packages/fory/lib/src/exception/`, which
is overly Java-style for idiomatic Dart.

## What needs to be done?

- Merge all runtime exception classes from:
  - `exception/**`
  - `codegen/exception/**`
  into a single file: `dart/packages/fory/lib/src/fory_exception.dart`

- Update all imports across serializers, resolvers, context, and codegen
base to point to the new file.
- Delete the `exception/` subdirectory and the `codegen/exception/`
subdirectory.

## Does this introduce any user-facing change?

- [x] Does this introduce any public API change? (import paths change)
- [ ] Does this introduce any binary protocol compatibility change?

## Related

- Requested in #3434 review:
#3434 (comment)

Author: yash-agarwa-l

dart/packages/fory-test/test/config_test/size_guard_test.dart

@@ -21,7 +21,7 @@ library;
 
 import 'dart:typed_data';
 import 'package:fory/fory.dart';
-import 'package:fory/src/exception/fory_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:test/test.dart';
 
 void main() {

dart/packages/fory/lib/src/codegen/analyze/impl/annotation/class_annotation_analyzer.dart

@@ -24,7 +24,7 @@ import 'package:fory/src/codegen/analyze/analysis_type_identifier.dart';
 import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart';
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/annotation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 
 class ClassAnnotationAnalyzer {
   const ClassAnnotationAnalyzer();

dart/packages/fory/lib/src/codegen/analyze/impl/annotation/enum_annotation_analyzer.dart

@@ -25,7 +25,7 @@ import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart'
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
 import 'package:fory/src/annotation/fory_enum.dart';
-import 'package:fory/src/codegen/exception/annotation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 
 class EnumAnnotationAnalyzer {
   const EnumAnnotationAnalyzer();

dart/packages/fory/lib/src/codegen/analyze/impl/annotation/key_annotation_analyzer.dart

@@ -23,7 +23,7 @@ import 'package:fory/src/codegen/analyze/analysis_type_identifier.dart';
 import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart';
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/annotation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:fory/src/annotation/fory_key.dart';
 
 class KeyAnnotationAnalyzer {

dart/packages/fory/lib/src/codegen/analyze/impl/annotation/uint_annotation_analyzer.dart

@@ -23,7 +23,7 @@ import 'package:fory/src/codegen/analyze/analysis_type_identifier.dart';
 import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart';
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/annotation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:fory/src/const/types.dart';
 
 /// Result of uint annotation analysis

dart/packages/fory/lib/src/codegen/analyze/impl/constructor/constructor_analyzer.dart

@@ -29,7 +29,7 @@ import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/constructor_param.dart';
 import 'package:fory/src/codegen/entity/constructor_params.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/constraint_violation_exception.dart'
+import 'package:fory/src/fory_exception.dart'
     show
         CircularIncapableRisk,
         InformalConstructorParamException,

dart/packages/fory/lib/src/codegen/analyze/impl/field/access_info_analyzer.dart

@@ -23,7 +23,7 @@ import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart'
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/constructor_params.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/field_exception.dart'
+import 'package:fory/src/fory_exception.dart'
     show FieldAccessErrorType, FieldAccessException;
 import 'package:fory/src/codegen/meta/impl/field_spec_immutable.dart';
 import 'package:fory/src/codegen/meta/impl/fields_spec_generator.dart';

dart/packages/fory/lib/src/codegen/analyze/impl/field/field_analyzer_impl.dart

@@ -33,7 +33,7 @@ import 'package:fory/src/codegen/analyze/interface/field_analyzer.dart';
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/either.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/constraint_violation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:fory/src/codegen/meta/impl/field_spec_immutable.dart';
 import 'package:fory/src/codegen/meta/impl/type_spec_generator.dart';
 import 'package:fory/src/codegen/meta/public_accessor_descriptor.dart';

dart/packages/fory/lib/src/codegen/analyze/impl/struct/custom_type_analyzer.dart

@@ -21,7 +21,7 @@ import 'package:analyzer/dart/element/element.dart';
 import 'package:fory/src/codegen/analyze/type_analysis_models.dart';
 import 'package:fory/src/codegen/analyze/analyzer.dart';
 import 'package:fory/src/codegen/entity/either.dart';
-import 'package:fory/src/codegen/exception/annotation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:fory/src/const/dart_type.dart';
 
 class CustomTypeAnalyzer {

dart/packages/fory/lib/src/codegen/analyze/impl/type/type_system_analyzer.dart

@@ -26,7 +26,7 @@ import 'package:fory/src/codegen/analyze/annotation/require_location_level.dart'
 import 'package:fory/src/codegen/const/location_level.dart';
 import 'package:fory/src/codegen/entity/either.dart';
 import 'package:fory/src/codegen/entity/location_mark.dart';
-import 'package:fory/src/codegen/exception/constraint_violation_exception.dart';
+import 'package:fory/src/fory_exception.dart';
 import 'package:fory/src/const/dart_type.dart';
 
 class TypeSystemAnalyzer {
@@ -41,7 +41,7 @@ class TypeSystemAnalyzer {
     Either<ObjectTypeAnalysis, DartTypeEnum> res =
         Analyzer.customTypeAnalyzer.resolveType(element);
     if (res.isRight) {
-      throw UnsupportedTypeException(
+      throw CodegenUnsupportedTypeException(
         locationMark.libPath,
         locationMark.clsName,
         locationMark.fieldName!,