fix(aura-cli, aura-runner): review findings — duplicate --override refusal, live discovery prose, neutral JSON refusal

In-cycle fixes for the independent review of the #319 package, RED-first
for both Importants. A repeated --override path now refuses at the shared
lexer (exit 2, path named) instead of panicking exit 101 through
reopen_all — which also un-misattributes the campaign leg's collision
prose for duplicates. override_paths' refusal points at aura graph
introspect --params (the retired --list-axes reference swept from every
live comment, one explicitly-historical mention remains). exec classifies
file targets through a Result-bearing peek: unparseable JSON refuses
neutrally before any leg is chosen. RunPresentation (single-variant)
removed; run_campaign_returning's contract note names its one deliberate
usage-class exit; C14's routing sentence and C20's family-builder
paragraph amended to current truth (superseded text to the history
sidecars); bench error strings and deletion blank-line runs tidied.

refs #319

crates/aura-cli/src/graph_construct.rs

@@ -642,10 +642,11 @@ pub fn introspect_cmd(cmd: crate::GraphIntrospectCmd, env: &aura_runner::project
     } else if let Some(target) = cmd.params.as_deref() {
         // --params <FILE|ID> (#196): the RAW composite param space — the one
         // namespace campaign axes are validated against
-        // (`validate_campaign_refs`) and `aura sweep --list-axes` prints
-        // (#328: the wrapped `<blueprint>.<node>.<param>` form was retired —
-        // there is exactly one axis namespace now, so the two discovery
-        // surfaces agree line-for-line, see `params_lines`'s own doc comment).
+        // (`validate_campaign_refs`) and `exec --override`'s own resolution
+        // (`override_paths`, member.rs) resolves against (#328: the wrapped
+        // `<blueprint>.<node>.<param>` form was retired — there is exactly
+        // one axis namespace now, so the two surfaces agree line-for-line,
+        // see `params_lines`'s own doc comment).
         match params_lines(target, env) {
             Ok(s) => print!("{s}"),
             Err(m) => {
@@ -938,8 +939,9 @@ fn resolve_blueprint_text(target: &str, env: &aura_runner::project::Env) -> Resu
 /// the same form `introspect --node` already uses for param kinds. Followed
 /// by one `{name}:{kind:?} default={value}` line per BOUND param (#328):
 /// `bound_param_space()`'s names are already RAW (#203), so no blueprint-name
-/// concatenation is needed — line-identical to the reconciled `--list-axes`
-/// bound pass (`list_blueprint_axes`, main.rs), same `render_value` lexicon.
+/// concatenation is needed — line-identical to the retired `aura sweep
+/// --list-axes`'s own bound pass (`list_blueprint_axes`, main.rs, gone with
+/// the #319 sugar retirement), same `render_value` lexicon.
 /// #331 delta re-review: the FILE target is a FOURTH freshly-authored-file
 /// intake this fn's own `composite_from_any` call had missed gating — a FILE
 /// routes through [`composite_from_authored_text`] instead; a content id