Generalises the family-member trace key (#105 foot-gun): derive it from the
axes that actually vary (not two hardcoded axis names), and render it as a
filesystem-conformant directory name on every major OS — charset [A-Za-z0-9._-],
case-less values (no case-insensitive-FS collision), length-bounded with an
FNV-1a fallback for the unbounded-grid edge.
Adds the first bool *param* node (LongOnly) and a momentum demo strategy
(Ema -> Sub -> Exposure -> LongOnly -> SimBroker) swept via a new
`aura sweep --strategy <sma|momentum>` selector — the empirical proof the
generic key works for a strategy whose params (incl. a bool) differ entirely
from the SMA-cross demo.
Boss-signed on the Step-5 grounding-check PASS (an independent fresh-context
agent): all 9 load-bearing current-behaviour assumptions ratified by green
tests; the end-to-end bool-param sweep path is correctly scoped as new
behaviour proven by new tests, not assumed. Workspace type-checks clean.
refs #105
Brummel
a8ba019d4d