Fix file browser for directories two levels deep

TreeWalk was only entering exact-match subtrees, missing intermediate
directories. Now enters all subtrees that are prefix of the target path.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/java/be/seeseepuff/webgit/service/GitService.java

@@ -464,13 +464,15 @@ public class GitService
 					if (dirPath != null && !dirPath.isEmpty())
 					{
 						tw.setFilter(PathFilter.create(dirPath));
-						// Walk into the directory
+						// Walk into the directory, entering intermediate subtrees as needed
 						while (tw.next())
 						{
-							if (tw.isSubtree() && tw.getPathString().equals(dirPath))
+							if (tw.isSubtree())
 							{
+								String path = tw.getPathString();
 								tw.enterSubtree();
-								break;
+								if (path.equals(dirPath))
+									break;
 							}
 						}
 					}

src/test/java/be/seeseepuff/webgit/service/GitServiceTest.java

@@ -373,6 +373,23 @@ class GitServiceTest
 		assertTrue(files.stream().anyMatch(f -> f.path().equals("README.md")));
 	}
 
+	@Test
+	void listFilesAtCommitReturnsNestedDirectoryContents() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		// Create a file two levels deep: src/main/Hello.txt
+		Path srcMain = worktreePath.resolve("myrepo/src/main");
+		Files.createDirectories(srcMain);
+		Files.writeString(srcMain.resolve("Hello.txt"), "hello");
+		gitService.stageFiles("myrepo", List.of("src/main/Hello.txt"));
+		gitService.commit("myrepo", "Add nested file");
+
+		var commits = gitService.listCommits("myrepo");
+		var files = gitService.listFilesAtCommit("myrepo", commits.getFirst().hash(), "src/main");
+		assertFalse(files.isEmpty());
+		assertTrue(files.stream().anyMatch(f -> f.path().equals("src/main/Hello.txt")));
+	}
+
 	@Test
 	void getFileContentAtCommitReturnsContent() throws GitAPIException, IOException
 	{