test: add UsesClass attributes to fix PHPUnit 12.5.x coverage warnings

PHPUnit 12.5.x is stricter about coverage attribution:
- Tests that touch classes not listed in CoversClass/UsesClass are marked
  risky or produce 'not a valid target' warnings with --coverage.

ToolExceptionTest:        #[UsesClass(DevkitException::class)]
  ToolException extends DevkitException — parent is touched implicitly.

ConfigurationExceptionTest: #[UsesClass(DevkitException::class)]
  Same reason.

QualityReportTest:         #[UsesClass(ToolResult::class)]
  QualityReport helper creates ToolResult instances directly.

Author: walmir-silva

tests/Unit/Exception/ConfigurationExceptionTest.php

@@ -8,9 +8,11 @@
 use KaririCode\Devkit\Exception\DevkitException;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 
 #[CoversClass(ConfigurationException::class)]
+#[UsesClass(DevkitException::class)]
 final class ConfigurationExceptionTest extends TestCase
 {
     #[Test]

tests/Unit/Exception/ToolExceptionTest.php

@@ -8,9 +8,11 @@
 use KaririCode\Devkit\Exception\ToolException;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 
 #[CoversClass(ToolException::class)]
+#[UsesClass(DevkitException::class)]
 final class ToolExceptionTest extends TestCase
 {
     #[Test]

tests/Unit/ValueObject/QualityReportTest.php

@@ -8,9 +8,11 @@
 use KaririCode\Devkit\ValueObject\ToolResult;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\Attributes\UsesClass;
 use PHPUnit\Framework\TestCase;
 
 #[CoversClass(QualityReport::class)]
+#[UsesClass(ToolResult::class)]
 final class QualityReportTest extends TestCase
 {
     private function makeResult(string $name, int $exitCode, float $elapsed = 0.1): ToolResult