fix(smartpdf): harden browser lifecycle, port handling, and PDF result metadata

test/test.port.ts

@@ -84,7 +84,8 @@ tap.test('should throw error when specific port is already in use', async () =>
     await instance2.start();
   } catch (error) {
     errorThrown = true;
-    expect(error.message).toInclude('already in use');
+    expect(error).toBeInstanceOf(Error);
+    expect((error as Error).message).toInclude('already in use');
   }
 
   expect(errorThrown).toBeTrue();
@@ -94,4 +95,4 @@ tap.test('should throw error when specific port is already in use', async () =>
 
 
 
-export default tap.start();
+export default tap.start();