docs(ledger, glossary, guide): the one-namespace axis prose

The C24 axis-discovery paragraph loses its obsolete rationale (names
prefixed by the wrapping, discovery pinned to the sweep verb) in favour
of the one-raw-namespace statement; C18 records the ratified #246
bound-override coincidence contract (param_space OR bound_param_space,
no schema flag) as the document-side absorption #328 demanded; the
glossary sweep and use entries, the authoring-guide worked block, and
the README axis examples move to raw names. Refusal transcripts quote
the byte-actual binary output (review caught an invented aura: error:
prefix; the campaign-validate transcript shows the real fault_block
shape). Frozen corpora (fieldtests/, *.history.md) keep their
historical wrapped prose.

refs #328

docs/design/contracts/c18-registry.md

@@ -133,6 +133,18 @@ show <content-id>` prints a registered document's canonical bytes (#300), so the
 generate → retrieve → hand-extend → re-register loop needs no direct store
 filesystem access.
 
+**The bound-override coincidence (#246, ratified #328).** A campaign axis naming a
+**bound** param of the referenced blueprint is deliberately accepted alongside one
+naming an open param: `validate_campaign_refs` checks each axis's name against
+`param_space()` **OR** `bound_param_space()` — the bound value stands as the
+axis's default, and the axis's own values re-open it for that campaign. There is
+no schema flag distinguishing the two cases (no `open`/`bound` marker on the axis
+entry); name coincidence against one of the two namespaces IS the mechanism, and
+the referenced blueprint is the single source of truth for which namespace a name
+falls in. Pinned by
+`referential_tier_accepts_a_kind_correct_axis_over_a_bound_param`
+(`aura-registry/src/lib.rs`).
+
 **The campaign executor.** `aura campaign run <file|content-id>` executes a
 campaign (a file is register-then-run sugar; the content id is canonical): a
 zero-fault referential gate, then the process pipeline. The executable shape is