fix(sonar): use dedicated File assertions (S5838)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KW6yskY3pE759XUg2UUtf8

Author: dfa1

cli/src/test/java/io/github/dfa1/vortex/cli/ImportCommandTest.java

@@ -200,8 +200,8 @@ void ownerCanStillReadAndWriteAfterRestricting(@TempDir Path tmp) throws IOExcep
             // Then — this is the non-POSIX equivalent of the POSIX branch's `rw-------`
             // FileAttribute; it must not lock the owner itself out of the file it just created
             assertThat(result).isEqualTo(file);
-            assertThat(file.toFile().canRead()).isTrue();
-            assertThat(file.toFile().canWrite()).isTrue();
+            assertThat(file.toFile()).canRead();
+            assertThat(file.toFile()).canWrite();
         }
     }
 }