Four CLI paths indexed vectors without checking their size and crashed
with SIGSEGV on malformed input:
- A project inherits_group whose length is not the filament count plus
the process and printer entries was split by position. It is now
ignored with a warning, as if the project had none.
- An assemble list object with an empty filaments list passed validation
and was then read at index 0. It is now rejected as a config error, as
is a negative filament id.
- --slice N --arrange 1 on a project without plate metadata read the
missing plate data. It now falls back to the plate's own filaments,
like the other plate data reads.
- --assemble with no input model built an object with no volumes. It is
now rejected as invalid parameters.
A tests/cli script covers each case through the binary, since all four
live inline in CLI::run().
