Two live-play problems, both auto-handled by gig-up.sh so nothing lives in
PLN's head at gig time:

1. MIDI-burst CRACKS — root cause was NOT samples or RT priority (rtprio 95 is
   fine): the CPU was capped at max_perf_pct=55 (the quiet/cool desk regime),
   so a control sweep's CPU burst starved the audio thread -> xrun. gig-up now
   ASSERTS Standard (uncapped, governor performance) on launch via
   perf.set_mode('standard') — which also writes the desired-state file so the
   Bridge watcher holds it. Revert to Cool in the tray when done; skip with
   GIG_PERF=off. Confirmed live: toggling to Standard killed the cracks.

2. LAZY-LOAD cracks — gen_preload() runs setlist_samples.py --last N --emit-sc
   into preload.scd before boot; start_and_midi.scd loads it after
   SCLOrkSynths.load, warming just the recent set's samples (last 15 tracks =
   55 folders vs the whole library). setlist_samples.py also gained bare-name
   track resolution (find under live/). preload.scd + gig-sclang.log gitignored.