refactor: add clearCache/evict to OpenApiSpecLoader and free cache after coverage

Add clearCache() and evict() methods to OpenApiSpecLoader so cached spec
data can be released without losing configuration. Call clearCache() in
the coverage extension after computing results, freeing large spec arrays
from memory at the earliest opportunity.

Author: wadakatu

src/OpenApiSpecLoader.php

@@ -79,6 +79,22 @@ public static function load(string $specName): array
         return $decoded;
     }
 
+    /**
+     * Clear only the cached specs, keeping basePath and stripPrefixes intact.
+     */
+    public static function clearCache(): void
+    {
+        self::$cache = [];
+    }
+
+    /**
+     * Remove a single spec from the cache.
+     */
+    public static function evict(string $specName): void
+    {
+        unset(self::$cache[$specName]);
+    }
+
     public static function reset(): void
     {
         self::$basePath = null;

src/PHPUnit/OpenApiCoverageExtension.php

@@ -79,6 +79,9 @@ public function notify(ExecutionFinished $event): void
             {
                 $results = $this->computeAllResults();
 
+                // Free cached spec data now that coverage has been computed
+                OpenApiSpecLoader::clearCache();
+
                 if ($results === []) {
                     return;
                 }

tests/Unit/OpenApiSpecLoaderTest.php

@@ -105,4 +105,45 @@ public function reset_clears_all_state(): void
         $this->expectException(RuntimeException::class);
         OpenApiSpecLoader::getBasePath();
     }
+
+    #[Test]
+    public function clear_cache_keeps_config(): void
+    {
+        $fixturesPath = __DIR__ . '/../fixtures/specs';
+        OpenApiSpecLoader::configure($fixturesPath, ['/api']);
+
+        // Load to populate cache
+        OpenApiSpecLoader::load('petstore-3.0');
+
+        OpenApiSpecLoader::clearCache();
+
+        // Config is preserved
+        $this->assertSame($fixturesPath, OpenApiSpecLoader::getBasePath());
+        $this->assertSame(['/api'], OpenApiSpecLoader::getStripPrefixes());
+
+        // Cache is cleared — next load reads from disk again
+        $spec = OpenApiSpecLoader::load('petstore-3.0');
+        $this->assertSame('3.0.3', $spec['openapi']);
+    }
+
+    #[Test]
+    public function evict_removes_single_spec_from_cache(): void
+    {
+        $fixturesPath = __DIR__ . '/../fixtures/specs';
+        OpenApiSpecLoader::configure($fixturesPath);
+
+        // Load two specs
+        $first30 = OpenApiSpecLoader::load('petstore-3.0');
+        $first31 = OpenApiSpecLoader::load('petstore-3.1');
+
+        // Evict only 3.0
+        OpenApiSpecLoader::evict('petstore-3.0');
+
+        // 3.1 still cached (same reference)
+        $this->assertSame($first31, OpenApiSpecLoader::load('petstore-3.1'));
+
+        // 3.0 reloaded from disk (equal but fresh instance)
+        $reloaded30 = OpenApiSpecLoader::load('petstore-3.0');
+        $this->assertSame($first30, $reloaded30);
+    }
 }