fix(ci): exclude DiscoveryException from PCOV coverage tracking

Root cause: DiscoveryException extends \RuntimeException (a native PHP
class). PCOV cannot properly instrument classes whose constructor chain
leads into native C-extension methods, causing PHPUnit 12 to emit
'not a valid target for code coverage' warnings on every test in
DiscoveryExceptionTest — regardless of failOnWarning sed patches.

Fix: activate coverage_exclude in devkit.php so kcode generates
phpunit.xml.dist with src/Exception excluded from the coverage source.
This eliminates the warning at the PCOV instrumentation level, making
it sed-independent and CI-safe across all environment configurations.

Changes:
- devkit.php: uncomment coverage_exclude => ['src/Exception']
- DiscoveryExceptionTest: remove #[CoversClass(DiscoveryException)]
  (invalid target, class excluded from coverage)
- DirectoryScannerTest: remove #[CoversClass(DiscoveryException)] and
  its now-unused import (class excluded from coverage)

Verified: kcode quality 4/4, kcode test 222/222 (0 warnings)

Author: walmir-silva

devkit.php

@@ -43,7 +43,7 @@
     // ],
 
     // ── Coverage ──────────────────────────────────────────────
-    // 'coverage_exclude' => ['src/Exception'],
+    'coverage_exclude' => ['src/Exception'],
 
     // ── Code Style (MERGED with KaririCode defaults) ──────────
     // 'cs_fixer_rules' => [

tests/Unit/Exception/DiscoveryExceptionTest.php

@@ -5,10 +5,11 @@
 namespace KaririCode\ClassDiscovery\Tests\Unit\Exception;
 
 use KaririCode\ClassDiscovery\Exception\DiscoveryException;
-use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 
-#[CoversClass(DiscoveryException::class)]
+// DiscoveryException is excluded from coverage (src/Exception) in devkit.php —
+// PCOV cannot instrument classes extending native PHP exceptions (RuntimeException).
+// Tests still exercise and assert all named constructors; only coverage tracking is skipped.
 final class DiscoveryExceptionTest extends TestCase
 {
     #[\PHPUnit\Framework\Attributes\DataProvider('namedConstructorProvider')]

tests/Unit/Scanner/DirectoryScannerTest.php

@@ -8,7 +8,6 @@
 use KaririCode\ClassDiscovery\Contract\ClassFilter;
 use KaririCode\ClassDiscovery\Contract\DiscoveryResult;
 use KaririCode\ClassDiscovery\Contract\NamespaceResolver;
-use KaririCode\ClassDiscovery\Exception\DiscoveryException;
 use KaririCode\ClassDiscovery\Result\ClassMetadata;
 use KaririCode\ClassDiscovery\Result\DiscoveryResult as ConcreteDiscoveryResult;
 use KaririCode\ClassDiscovery\Scanner\DirectoryScanner;
@@ -19,7 +18,6 @@
 use PHPUnit\Framework\TestCase;
 
 #[CoversClass(DirectoryScanner::class)]
-#[CoversClass(DiscoveryException::class)]
 #[UsesClass(FileScanner::class)]
 #[UsesClass(ConcreteDiscoveryResult::class)]
 #[UsesClass(ClassMetadata::class)]