Teach the Linux AFP Entry ID smoke test to treat VOL:PATH arguments like normal NetWare paths instead of sending the full string as the AFP path component.
The WebSDK documents AFP Get Entry ID From Path Name as taking a NetWare directory handle plus a path string. A user-supplied path such as SYS:PUBLIC therefore needs a directory handle for the SYS volume root and a relative AFP path of PUBLIC; sending SYS:PUBLIC as the AFP path with directory handle zero makes the server reject the request with Invalid Path before the actual AFP lookup is useful.
Use the existing ncpfs/libncp request path to allocate a temporary directory handle for the volume root when the test receives a VOL:PATH argument and no explicit --dir-handle was supplied. Keep --raw-path for callers that want to send the path exactly as typed, and add --allow-invalid-path so negative path-resolution tests can distinguish Invalid Path from Invalid Namespace.
Also add failure diagnostics to the server-side AFP path lookup so unsupported-backend, boundary-check, path-resolution, and stat failures are visible in the mars_nwe log.
This changes only the Linux smoke test and debug logging; it does not change successful AFP protocol semantics.
Add an optional Linux-side smoke test for the first implemented NetWare AFP endpoint.
The WebSDK documents NCP 0x2222/35/12 AFP Get Entry ID From Path Name as taking a NetWare directory handle and path string and returning a 32-bit AFP entry id. MARS-NWE now has a guarded implementation of that probe when the optional Netatalk/libatalk backend is compiled in, but exercising it does not require a real AppleTalk workstation.
Use the ncpfs/libncp client library as the test transport. ncpfs is commonly available on Linux mars_nwe test hosts and its NWRequestSimple() helper builds the same length-prefixed subfunction request format used by normal libncp callers. The test accepts standard ncpfs connection options such as -S, -U, -P, and -n, sends NCP 0x23/0x0c, and prints the returned entry id.
Keep the test out of normal builds behind MARS_NWE_BUILD_LINUX_TESTS because it depends on host ncpfs development headers/library and on a running server. Add an --allow-invalid-namespace mode so builds without the Netatalk backend can still run a negative smoke test and verify that AFP remains unavailable.
This adds test infrastructure only and does not change server protocol behavior.
