audit: bound-override cycle close — drift-clean after one comment fix

Architect drift review over 0ad8fc6..e4fb64d: the C12 amendment's words
match the shipped behaviour exactly (identity from the authored document,
run/mc closed-guards untouched, bound = overridable default; every
point-binding reload goes through the reopened probe). One medium item
fixed here: the unknown-axis test's rationale comment still described the
retired 'fully bound; nothing to sweep' refusal. Noted as low-priority
debt, unchanged: the four override-derivation helpers across the wrapped/
raw coordinate systems are candidates for consolidation when the next
family boundary appears.

refs #246

crates/aura-cli/tests/cli_run.rs

@@ -4102,8 +4102,8 @@ fn aura_sweep_persists_the_canonical_blueprint_keyed_by_topology_hash() {
 
 /// An `--axis` name that does not resolve against the loaded blueprint's param_space
 /// fails clean (a named BindError, non-zero exit), not a panic. The OPEN fixture has
-/// sweepable knobs, so a nonsense axis name (`nope`) is genuinely unknown — distinct
-/// from a fully-bound blueprint, which is refused earlier as "nothing to sweep".
+/// sweepable knobs, so a nonsense axis name (`nope`) is genuinely unknown — it names
+/// neither an open knob nor a bound param (#246: a bound name would re-open instead).
 #[test]
 fn aura_sweep_rejects_an_unknown_axis() {
     let fixture = format!("{}/examples/r_sma_open.json", env!("CARGO_MANIFEST_DIR"));