Add test coverage for SetterMethod::accept() exception handling

This commit adds two new test cases to improve code coverage for the
SetterMethod::accept() method's exception handling logic:

1. testAcceptWithUnboundException: Tests that Unbound exceptions are
   properly re-thrown when isOptional is false
2. testAcceptWithUnboundExceptionOptional: Tests that Unbound exceptions
   are silently handled (not re-thrown) when isOptional is true

These tests cover the previously untested catch block in SetterMethod::accept(),
improving the method's line coverage from ~75% to 93.75%.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: koriym

tests/di/SetterMethodTest.php

@@ -7,6 +7,7 @@
 use PHPUnit\Framework\TestCase;
 use Ray\Di\Exception\Unbound;
 use ReflectionMethod;
+use ReflectionParameter;
 
 use function spl_object_hash;
 
@@ -41,4 +42,115 @@ public function testUnbound(): void
         $car = new FakeCar(new FakeEngine());
         $this->setterMethods->__invoke($car, $container);
     }
+
+    public function testAcceptWithUnboundException(): void
+    {
+        $this->expectException(Unbound::class);
+        $method = new ReflectionMethod(FakeCar::class, 'setTires');
+        $setterMethod = new SetterMethod($method, new Name(Name::ANY));
+
+        $visitor = new class implements VisitorInterface
+        {
+            public function visitSetterMethod(string $method, Arguments $arguments): void
+            {
+                throw new Unbound(FakeTyreInterface::class);
+            }
+
+            public function visitDependency(NewInstance $newInstance, ?string $postConstruct, bool $isSingleton): void
+            {
+            }
+
+            public function visitProvider(Dependency $dependency, string $context, bool $isSingleton): string
+            {
+                return '';
+            }
+
+            /** @param mixed $value */
+            public function visitInstance($value): string
+            {
+                return '';
+            }
+
+            public function visitAspectBind(\Ray\Aop\Bind $aopBind): void
+            {
+            }
+
+            public function visitNewInstance(string $class, SetterMethods $setterMethods, ?Arguments $arguments, ?AspectBind $bind): void
+            {
+            }
+
+            /** @param array<SetterMethod> $setterMethods */
+            public function visitSetterMethods(array $setterMethods): void
+            {
+            }
+
+            /** @param array<Argument> $arguments */
+            public function visitArguments(array $arguments): void
+            {
+            }
+
+            /** @param mixed $defaultValue */
+            public function visitArgument(string $index, bool $isDefaultAvailable, $defaultValue, ReflectionParameter $parameter): void
+            {
+            }
+        };
+
+        $setterMethod->accept($visitor);
+    }
+
+    public function testAcceptWithUnboundExceptionOptional(): void
+    {
+        $method = new ReflectionMethod(FakeCar::class, 'setTires');
+        $setterMethod = new SetterMethod($method, new Name(Name::ANY));
+        $setterMethod->setOptional();
+
+        $visitor = new class implements VisitorInterface
+        {
+            public function visitSetterMethod(string $method, Arguments $arguments): void
+            {
+                throw new Unbound(FakeTyreInterface::class);
+            }
+
+            public function visitDependency(NewInstance $newInstance, ?string $postConstruct, bool $isSingleton): void
+            {
+            }
+
+            public function visitProvider(Dependency $dependency, string $context, bool $isSingleton): string
+            {
+                return '';
+            }
+
+            /** @param mixed $value */
+            public function visitInstance($value): string
+            {
+                return '';
+            }
+
+            public function visitAspectBind(\Ray\Aop\Bind $aopBind): void
+            {
+            }
+
+            public function visitNewInstance(string $class, SetterMethods $setterMethods, ?Arguments $arguments, ?AspectBind $bind): void
+            {
+            }
+
+            /** @param array<SetterMethod> $setterMethods */
+            public function visitSetterMethods(array $setterMethods): void
+            {
+            }
+
+            /** @param array<Argument> $arguments */
+            public function visitArguments(array $arguments): void
+            {
+            }
+
+            /** @param mixed $defaultValue */
+            public function visitArgument(string $index, bool $isDefaultAvailable, $defaultValue, ReflectionParameter $parameter): void
+            {
+            }
+        };
+
+        $result = $setterMethod->accept($visitor);
+        $this->assertNull($result);
+    }
 }