Make `mkdir` follow intermediate symbolic links

[abhinavgautam01]

Description

WorkspaceFilesystem.mkdir does not use the shared symbolic-link resolver when it walks the target path. Its lookupChild helper reads each directory entry directly and treats every node other than a directory as an ENOTDIR error. A symbolic link to a directory therefore blocks directory creation instead of resolving transparently.

For example:

await fs.mkdir("/real");
await fs.symlink("/real", "/alias");
await fs.mkdir("/alias/new-directory");

The last call currently throws ENOTDIR. It should create /real/new-directory.

Other write paths, including writeFile, follow symbolic links and enforce the shared 40-hop limit. mkdir should provide the same behavior for absolute links, relative links, chains, dangling links and loops.

Expected outcome

• Follow symbolic links in intermediate path segments before creating a directory.
• Create the new directory under the resolved parent inode.
• Preserve ENOTDIR when the resolved parent segment is a file.
• Return ENOENT for a dangling parent link and ELOOP after more than 40 link traversals.
• Apply the same behavior to recursive directory creation.
• Add regression tests for absolute and relative links, recursive creation, dangling links and loops.