[opendev9]

Problem

Follow-up to #29, which started sending the real dirent mode as kind to Hub Authority. The guard it added treated an unknown kind as fatal:

if (... || (!S_ISDIR(mode) && !S_ISREG(mode))) {
    g_free(name);
    goto done;            /* aborts the whole 512-entry chunk */
}

filter_chunk() returning -1 makes cf_acl_filter_dirents() return NULL, which hides every child. So one dirent whose mode is neither regular nor directory empties its entire directory page. That mode is reachable: server/pack-dir.c defines and handles S_IFLNK.

Change

• invalid names (empty, containing /, ., ..) still abort the chunk — that is corrupt input, not a per-child decision, and the existing contract keeps it
• an entry with no Authority kind is continued: it gets no permission below and stays hidden, exactly like a denied sibling
• included records the children that produced a checks[] entry, so permissions[i] still maps to the right dirent and the visible list stays aligned
• an all-skipped chunk returns 0 (empty page) instead of a fail-closed NULL

Verification

• python3 -m unittest discover -s tests -p 'test_cf_*.py' → 12 tests OK, including 4 new contracts: skip-vs-abort separation, index alignment (p=included, never p=begin), empty chunk, invalid-name abort
• python3 tests/test_v2_no_managed_library.py → OK
• C syntax check not run locally (needs the autotools build to generate seafile-object.h); native MariaDB/Hub integration still requires the manual environment, unchanged by this PR.