(fix): remove stale purge call from cache invalidation test

The purge method was removed from the Resolver interface. The test
now relies on TTL expiry alone to verify re-resolution, which is
what it was actually testing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: abnegate

tests/Integration/EdgeIntegrationTest.php

@@ -258,15 +258,13 @@ public function testCacheInvalidationForcesReResolve(): void
         $first = $adapter->route('invaldb');
         $this->assertFalse($first->metadata['cached']);
 
-        $resolver->purge('invaldb');
-
         // Wait for the routing table cache to expire
         sleep(2);
 
         $second = $adapter->route('invaldb');
         $this->assertFalse($second->metadata['cached']);
 
-        // Should have resolved twice
+        // Should have resolved twice (cache expired, forced re-resolve)
         $this->assertSame(2, $resolver->getResolveCount());
     }
 
@@ -440,11 +438,6 @@ public function getResolveCount(): int
     {
         return $this->resolveCount;
     }
-
-    public function purge(string $data): void
-    {
-        unset($this->databases[$data]);
-    }
 }
 
 /**