Wwstage dirfilekeep checked only the first 5 chars of ".combined.ww"
(.comb), leaving a latent over-filter for hypothetical filenames of
shape .combXXXX.ww. Cstage enumerate_dir_ww in cmd/ww/main.c uses
strcmp on the full 12-char tail; mirror that here per rule-10
symmetric-stages. Extends the nested-if cascade to also gate on
'i','n','e','d' at offsets nlen-7..nlen-4; the trailing .ww is
already enforced by the function's leading early-out, so re-checking
those three positions would be dead and is called out in the comment.
No corpus trigger today; bootstrap ww2==ww3==ww4 byte-id holds.
Predecessor: #22 dir-enum (9e0816e) introduced the predicate.
115/115 ok. ww2 == ww3 == ww4 byte-id.
Hojun-Cho
f9f0720804