Raise MapTileStore::PATH_CAPACITY from 64 to 80 so the mount buffer
(PATH_CAPACITY + 4) holds the 80-character mounted tile path produced by
a maximum-length (31-char) pack ID with full-width tile coordinates.
Pre-fix, any tile with a two-digit x or y returned INVALID_ARGUMENT from
the mount-prefix snprintf, which MapTilePack maps to IO_ERROR and the UI
shows as 'Tile I/O error' even though the file exists and is intact.
The host regression test added in the prior commit now passes under both
strict C++11 and ASan/UBSan; reverting this change fails it.
A 31-character pack ID makes mounted tile paths
(/sd/pyxis-map/packs/<id>/tiles/<z>/<x>/<y>.png) exceed the 68-byte mount
buffer once either x or y is two digits, so beginRead returns
INVALID_ARGUMENT and the UI shows 'Tile I/O error' at z4+ even though the
file exists and is intact.
Compiles the unmodified MapTilePack/MapTileStoreSD/SDAccess/codec/manifest
sources against small Arduino/FreeRTOS host shims. The core section (no
card needed) drives the real store with a model of the mount-prefix
arithmetic and asserts the 31-char-ID boundary loads at z4/z5; an optional
end-to-end section runs the real MapTilePack over a bound card root when
/sd is writable.
Fails on the current 64-byte PATH_CAPACITY: red by design.
Torlando