rename: retire the stage1-* family for the r-family (r-sma / r-breakout / r-meanrev)

The stage1 ordinal has been dead vocabulary since the C10 reframe dropped
the two-stage research model: a 1 structurally implies a 2 that no longer
exists. The family is renamed by its live discriminator - the R yardstick -
with members named by their signal, uniform with their signal-named
siblings (sma, macd, momentum):

- selectors: stage1-r -> r-sma, stage1-breakout -> r-breakout,
  stage1-meanrev -> r-meanrev (old tokens are usage errors, exit 2 - no
  silent alias)
- identifiers: Strategy::RSma/RBreakout/RMeanRev, HarnessKind::RSma,
  r_sma_*/r_breakout_*/r_meanrev_*, wrap_r, run_signal_r, RGrid, R_SMA_*
- persisted identity: the sma_signal composite (param prefix
  sma_signal.fast.length / .slow.length; fixtures regenerated; content-ids
  shift - no test pins a literal hash, the registry parses no record names)
- e2e test files git-mv'd to r_sma_e2e / r_breakout_e2e / r_meanrev_e2e
- dead Stage-1/Stage-2 prose reworded to post-C10 vocabulary across
  rustdoc, Cargo.tomls, ledger live lines, and the glossary (historical
  entries stay; fieldtests corpus untouched)
- CLAUDE.md invariant 7 rewritten to record the ratified C10 reframe
  faithfully (the token-swap alone would have laundered the retired
  gated-currency/realistic-broker design into unmarked live prose); the
  unbacked account-mode clause dropped

Verification: cargo build/test --workspace green (51 targets), clippy
-D warnings clean, doc build clean, acceptance grep gate leaves exactly
the one resampling-stage false positive (harness.rs), smoke: --harness
r-sma runs, --harness stage1-r exits 2 with the new usage line.

Decision log: forks and rationale recorded on the issue (reconciliation
+ implementation-phase comments).

closes #174

crates/aura-engine/Cargo.toml

@@ -22,7 +22,7 @@ serde_json = { workspace = true }
 
 [dev-dependencies]
 # aura-std is a TEST-ONLY dependency: the engine's own integration tests
-# (stage1_r_e2e, random_sweep_e2e, ger40_breakout) drive real standard nodes through
+# (r_sma_e2e, random_sweep_e2e, ger40_breakout) drive real standard nodes through
 # a bootstrapped Harness. The engine's library code never names a concrete node — it
 # routes type-erased Scalar records (summarize_r reads the PositionManagement record
 # positionally, by index), so aura-std stays out of [dependencies] and the engine is

crates/aura-engine/tests/r_meanrev_e2e.rs

@@ -3,7 +3,7 @@
 //! {Gt, Gt} -> {Latch, Latch} -> Sub = bias in {-1,0,+1}. Tests the FADE
 //! direction (price above mean+k*sigma -> short -1; below mean-k*sigma -> long
 //! +1), the latched hold, and that no fade fires on a flat series. Built
-//! straight from aura-std nodes (no CLI dependency); mirrors stage1_breakout_e2e.
+//! straight from aura-std nodes (no CLI dependency); mirrors r_breakout_e2e.
 
 use aura_core::{Scalar, Timestamp};
 use aura_engine::{GraphBuilder, Harness, Source, VecSource};

crates/aura-engine/tests/r_sma_e2e.rs

@@ -1,4 +1,4 @@
-//! Stage-1 R E2E: a synthetic bias+price chain through stop-rule + position-management,
+//! R E2E: a synthetic bias+price chain through stop-rule + position-management,
 //! recorded and folded by `summarize_r`. Also guards the dense-record layout contract
 //! (aura-std's `PM_FIELD_NAMES`/`PM_RECORD_KINDS` vs the column indices `summarize_r`
 //! reads).
@@ -94,7 +94,7 @@ fn synthetic_long_then_stop_produces_a_sane_rmetric() {
 
 /// Drive the real cross-crate chain `stop -> PositionManagement` over a `(bias, price)`
 /// path, collecting the producer's dense records (decoded by the producer's own
-/// `PM_RECORD_KINDS`, the wire contract) into a ledger — the recorded stream a Stage-1
+/// `PM_RECORD_KINDS`, the wire contract) into a ledger — the recorded stream an R-yardstick
 /// run would persist. Per-cycle bias (not constant) so a fixture can drop bias to 0 to
 /// forbid the immediate re-entry after a stop. The fold is left to the caller so the
 /// same recorded ledger can be summarized at several `round_trip_cost` values.
@@ -124,7 +124,7 @@ fn run_chain_ledger(stop: &mut dyn Node, path: &[(f64, f64)]) -> Vec<(Timestamp,
 
 /// Drive the real cross-crate chain `stop -> PositionManagement -> summarize_r`
 /// over a `(bias, price)` path. This is the actual producer->consumer seam,
-/// node-by-node; the resulting `RMetrics` is what a recorded Stage-1 run would report.
+/// node-by-node; the resulting `RMetrics` is what a recorded R-yardstick run would report.
 fn run_chain(stop: &mut dyn Node, path: &[(f64, f64)]) -> RMetrics {
     summarize_r(&run_chain_ledger(stop, path), &[])
 }

crates/aura-engine/tests/streaming_reduction_equivalence.rs

@@ -1,5 +1,5 @@
 //! Folded sink reductions are byte-for-byte equal to the raw-recorder path.
-//! Drives the folding sinks node-by-node (the `stage1_r_e2e.rs` direct-node
+//! Drives the folding sinks node-by-node (the `r_sma_e2e.rs` direct-node
 //! style) over a synthetic dense R-record + equity/exposure series, and asserts
 //! `summarize_r` over `GatedRecorder`'s emitted rows equals `summarize_r` over
 //! the full record, and a `SeriesReducer` summary equals `summarize`'s fields.