refactor(cli): retire the r-sma demo builder — topology now lives only as data (#159 cut 1b)

Cut 1b of the hard-wired demo retirement — the removal half. With the proven
example shipped in cut 1, delete the r-sma builder and its whole transitive
closure so no production function constructs the r-sma topology any more; it
exists only as data (crates/aura-cli/examples/r_sma{,_open}.json).

Deleted: sma_signal (the builder), r_sma_graph, run_r_sma (aura run --harness
r-sma), r_sma_sweep_family (aura sweep --strategy r-sma), the synthetic inline
r-sma walkforward/mc machinery (r_sma_space/r_sma_sweep_over/run_oos_r/
run_mc_r_bootstrap/mc_r_bootstrap_report + the walkforward_family RSma arm), both
fixture emitters, the round-trip + cut-1 byte-fidelity tests, the R_SMA_FAST/
SLOW/BIAS_SCALE consts, and the Strategy::RSma / HarnessKind::RSma / McArgs::RealR
variants. The three dissolved-verb synth sites (generalize/walkforward/mc
--strategy r-sma --real) now embed the shipped open example via include_str!
instead of building it — byte-safe, guarded by the unchanged dissolved-verb
real-archive goldens. The two now-redundant fixtures move to the examples
(deleted, ~40 readers repointed). The --cost-* flags on `aura run` retire with
the harness (their sole consumer was run_r_sma; cost-model coverage survives
engine/std/composites-level).

The retired demo surfaces (--harness r-sma, sweep/walkforward/mc --strategy r-sma
inline) have working data successors: aura run examples/r_sma.json, aura sweep
examples/r_sma_open.json --axis …, and the --strategy r-sma --real campaign path.

Deviation from the plan, noted: StopArm collapsed to StopRule in wrap_r's
signature (its only other variant, Open, died with r_sma_graph) — cleaner than
the planned vestigial single-variant enum; behaviour-preserving, touching
campaign_run.rs and the r-breakout/r-meanrev call sites.

Follow-up (not this cut): wrap_r's cost-node-building branch is now unreachable
(nothing passes Some(CostConfig) after run_r_sma's deletion) yet clippy-clean —
a latent cleanup for when the inline cost surface fully retires.

The stage1-r param-suffix remapping (r_sma_friendly_name + the FAST/SLOW/
STOP_LENGTH/STOP_K_SUFFIX consts) went dead and was removed, closing #167 by
deletion.

Verification (own, not the workflow's report): full `cargo test --workspace`
green; `cargo clippy --workspace --all-targets -- -D warnings` clean, no
dead-code residue; the cut-1 grade anchor (shipped_r_sma_example_reproduces_the_
builtin_grade) and the dissolved-verb real goldens (generalize/walkforward/mc
_dissolves_through_the_campaign_path) stay byte-identical. A first workflow
attempt was discarded after a subagent's `git checkout -- main.rs` recovery
silently reverted earlier tasks' edits (filed on the plugin tracker as
Brummel/Skills#23); this landing is the hardened re-run, verified by hand.

closes #167
refs #159

crates/aura-cli/tests/graph_construct.rs

@@ -436,7 +436,7 @@ fn registered_id(stdout: &str) -> String {
 #[test]
 fn graph_register_stores_and_prints_content_id() {
     let dir = temp_cwd("register");
-    let (stdout, stderr, code) = run_in(&dir, &["graph", "register", &fixture("sma_signal.json")]);
+    let (stdout, stderr, code) = run_in(&dir, &["graph", "register", &example("r_sma.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     // #194: the register verb prints the bare id — `registered blueprint <id> (<path>)`.
     assert!(!stdout.contains("content:"), "register prints the bare id, no content: prefix: {stdout}");
@@ -454,7 +454,7 @@ fn graph_register_stores_and_prints_content_id() {
 #[test]
 fn graph_register_is_idempotent() {
     let dir = temp_cwd("register-idempotent");
-    let bp = fixture("sma_signal.json");
+    let bp = example("r_sma.json");
     let (out1, err1, code1) = run_in(&dir, &["graph", "register", &bp]);
     let (out2, err2, code2) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(code1, Some(0), "first register: {out1} {err1}");
@@ -471,7 +471,7 @@ fn graph_register_is_idempotent() {
 fn graph_params_lists_raw_axis_namespace() {
     let dir = temp_cwd("params");
     let (stdout, stderr, code) =
-        run_in(&dir, &["graph", "introspect", "--params", &fixture("sma_signal_open.json")]);
+        run_in(&dir, &["graph", "introspect", "--params", &example("r_sma_open.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     assert_eq!(stdout, "fast.length:I64\nslow.length:I64\n", "the raw open params, in order");
 }
@@ -482,7 +482,7 @@ fn graph_params_lists_raw_axis_namespace() {
 #[test]
 fn graph_content_id_accepts_a_blueprint_file() {
     let dir = temp_cwd("content-id-file");
-    let bp = fixture("sma_signal.json");
+    let bp = example("r_sma.json");
     let (reg_out, reg_err, reg_code) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(reg_code, Some(0), "register: {reg_out} {reg_err}");
     let (id_out, id_err, id_code) = run_in(&dir, &["graph", "introspect", "--content-id", &bp]);
@@ -512,7 +512,7 @@ fn graph_introspect_mode_guard_still_exits_two_on_zero_or_two_modes() {
 #[test]
 fn graph_params_by_content_id_matches_params_by_file() {
     let dir = temp_cwd("params-by-id");
-    let bp = fixture("sma_signal_open.json");
+    let bp = example("r_sma_open.json");
     let (reg_out, reg_err, reg_code) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(reg_code, Some(0), "register: {reg_out} {reg_err}");
     let id = registered_id(&reg_out);
@@ -533,7 +533,7 @@ fn graph_params_by_content_id_matches_params_by_file() {
 #[test]
 fn graph_params_tolerates_content_prefix_on_target() {
     let dir = temp_cwd("params-content-prefix");
-    let bp = fixture("sma_signal_open.json");
+    let bp = example("r_sma_open.json");
     let (reg_out, reg_err, reg_code) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(reg_code, Some(0), "register: {reg_out} {reg_err}");
     let id = registered_id(&reg_out);