Reclaim daemon memory across the pools.
garry_pool_hygiene.RdAsks every daemon in the pools to release caches and return freed
heap pages to the operating system (glibc malloc_trim). With
deep = TRUE the daemons' jit caches are also evicted, forcing
recompiles on next use (roughly a second per map kernel, tens of
seconds per scan kernel); reserve that for memory pressure. Daemons
already trim at run start, and during a run once the task transients
since their last trim pass garry.daemon_gc_mb (see
garry_options()); call this between pipeline phases when the fleet
should idle lean.