audit(0066): cycle close — lift R-sweep/SQN rationale to ledger, drop ephemera

Cycle 0066 (#133) closed. The close audit (architect) found the family ratified against C12 axis-2 (rank-by-metric over the C18 family store) and the C10 R framing, with one [high] gap (swept-member manifest omitted the fixed R-defining params) fixed forward in 499121e.

- Ledger: a C10 realization note records the durable rationale -- SQN as the single-number sweep objective, the signal-only grid (the stop defines R, so varying it breaks cross-member SQN comparability -- the SQN100 #130 motivation), the R-metric rank vocabulary, and the manifest-completeness fix.
- Glossary: new 'R metrics' and 'SQN' entries.
- The ephemeral spec + plan are removed; the ledger + git history are the durable record.

Follow-ups filed: #135 (per-member --trace for the stage1-r sweep). refs #133

docs/design/INDEX.md

@@ -644,6 +644,22 @@ reconstruction loses precision; the stored `realized_r` is exact). Composites li
 acyclic. **Stage 2** (currency P&L, fixed-fractional compounding through the z⁻¹
 fill-edge register, realistic brokers consuming the position-event table) remains the
 deferred downstream layer, entered only after `E[R] > 0`.
+**Realization (cycle 0066).** SQN is now the operational single-number objective for
+ranking a Stage-1 sweep family by signal quality — C12 **axis-2 (argmax-metric)** over
+the C18 family store. `metric_cmp` (`aura-registry`) learns the higher-is-better R
+metrics `sqn`, `expectancy_r`, `net_expectancy_r`; a member with no `r` block sorts
+last (`NEG_INFINITY`), so a pip-only family ranked by an R metric degrades to ordinal
+order rather than erroring. `aura sweep --strategy stage1-r` produces the rankable R
+family, each member folding `summarize_r` into `RunMetrics.r`. The default grid varies
+**only the signal** (`fast`/`slow` SMA lengths), holding the stop and sizing fixed:
+`risk_budget` is R-invariant and `bias.scale` is sign-only under flat-1R (both
+degenerate axes for the ranked metric), and — load-bearing — the **stop defines 1R**,
+so varying it would change what R *means* per member and break cross-member SQN
+comparability (the motivation for the deferred n-normalized SQN100, #130). Each swept
+member's manifest records the fixed R-defining params (stop, scale) beside the floated
+knobs, so a member is reproducible from its own manifest (C18) and the constant-stop
+basis of comparability is auditable from the family record. Per-member `--trace` for
+the stage1-r sweep is refused explicitly (not a silent no-op) pending #135.
 
 ### C11 — Generalized sources; record-then-replay determinism boundary
 **Guarantee.** A source is anything that produces timestamped scalar streams —