mara hit this directly: setting an agent's memory cap to "16GB"
fails with 'invalid MemoryMax "16GB": expected a size such as
"8G"...'. Confirmed directly against a running systemd 260
(systemd-run -p MemoryMax=<value>): systemd's own parser accepts a
bare byte count, <digits>B, or <digits> plus exactly one uppercase
K/M/G/T, and rejects both "16GB" (redundant B after a multiplier)
and "16g" (lowercase) with "Invalid argument". So the prior
rejection of "16GB" matched systemd, but is bad UX for input a
human reasonably expects to work.
validate_memory_max now returns the value to store (not just an
ok/err verdict): it accepts 8gb/8Gb/8GB/8g/8G interchangeably and
normalizes all of them to systemd's own 8G form before it is ever
persisted or passed downstream. Also fixes the adjacent bug the same
investigation turned up: the old validator incorrectly accepted
lowercase (8g) even though systemd itself rejects it.
Updated both call sites (server.rs, dashboard/lifecycle_ops.rs) to
use the normalized return value. New test
friendly_size_spellings_normalize_to_systemds_own_form; flipped the
old "8GB should be rejected" assertion, which encoded the
human-hostile behavior this fixes.