Generalises the #105 foot-gun: the family-member trace key was derived from two
hardcoded axis names (f{fast}s{slow}), collision-free only over the built-in SMA
grid. It is now derived from the axes that actually VARY
(SweepBinder::varying_axes) and rendered as a filesystem-conformant directory
component:
- charset restricted to [A-Za-z0-9._-] (valid on Linux/Windows/macOS, also
URL-path- and cloud-sync-safe); any other byte sanitised;
- case-less values (i64/timestamp decimal, bool true/false, f64 via Display, no
scientific notation) so two members of one family never differ only by letter
case -> no silent overwrite on case-insensitive filesystems (NTFS/APFS);
- length-capped (MAX_KEY=200) with a version-stable FNV-1a fallback for the
unbounded-grid edge.
Pinned singleton axes are omitted; the SMA sweep's member dirs change from f2s4
to signals.trend.fast.length-2_signals.trend.slow.length-4 (its --trace
integration test + the stale prose updated accordingly).
Adds the first aura-std node with a bool *param*, LongOnly (a long-only exposure
gate: enabled=true clamps short exposure to >=0, false passes through) — the
block the momentum demo strategy (next commit) sweeps to prove the key generic
over a bool axis. The engine change is one additive pure read accessor; no
existing signature changes, trace state stays out of the engine.
Self-verified: cargo build --workspace, cargo test --workspace (all green incl.
the LongOnly node tests, the member_key worked-examples corpus, the varying_axes
accessor test, and the updated SMA sweep-trace integration test), cargo clippy
--workspace --all-targets -D warnings.
refs #105
Brummel
27f850dc52