Realizes #133 (cycle 0066): SQN becomes the single-number objective for ranking a
Stage-1 sweep family by R signal quality.
aura-registry — metric_cmp learns three higher-is-better R metrics (sqn,
expectancy_r, net_expectancy_r) that reach into RunReport.metrics.r; a member with
r:None sorts to the worst position (treated as -inf via total_cmp), so a pip-only
family ranked by an R metric degrades to ordinal order without error. The
UnknownMetric "known:" list is extended. No persistence change — the family store
already carries the r block.
aura-cli — `aura sweep --strategy stage1-r` sweeps the stage1-r harness over a
fast×slow SIGNAL grid (4 members), each folding the dense R-record via summarize_r so
its RunReport carries r:Some(..). The grid varies only the signal: the stop and
sizing are held fixed because risk_budget is R-invariant (#128) and bias.scale is
sign-only under flat-1R (both degenerate axes for the ranked metric), and because the
stop defines the R unit — varying it would break cross-member SQN comparability (the
motivation for the deferred SQN100, #130). The stage1-r topology is extracted into a
shared stage1_r_graph(.., fast_len, slow_len) helper: the single run binds
Some(2)/Some(4) (output byte-unchanged), only the sweep floats the knobs.
Per-member --trace tracing is deferred (a follow-up): rather than accept the flag and
silently write nothing (a quality-review catch), `aura sweep --strategy stage1-r
--trace` is refused explicitly (exit 2); --name records the rankable family.
Verification — a golden characterization test (stage1_r_single_run_output_golden,
added against HEAD before the refactor) verifies the helper extraction is
byte-preserving; full workspace suite 521 passed / 0 failed; clippy --all-targets
-D warnings clean. The grounding-check that signed the spec first BLOCKed a false
"already byte-pinned" claim, which is why the golden is added rather than assumed.
All load-bearing forks (signal-only grid, None-sorts-worst, --trace refusal, helper
extraction, golden shape) are recorded on the #133 decision log.
closes#133
refs #117#130
Brummel
b8ed6f4858