fix(cli): the graph render positional shape-discriminates op-scripts like its siblings

aura graph <op-script.json> exited 2 mislabeling the valid JSON array
as 'blueprint document is not valid JSON' — dispatch_graph parsed the
render positional with the envelope-only blueprint_from_json while the
introspect siblings (register, --params, --content-id) route through
composite_from_any. The render positional now uses the same
shape-discriminating path (made pub(crate)); an op-script renders
byte-identically to its built envelope, and a genuinely-bad document
gets the shared honest error including the unresolved-namespace hint
(preserved verbatim in composite_from_any's envelope arm).

Verified: RED test green, full workspace suite green (independent
mini-verify).

closes #226

crates/aura-cli/src/graph_construct.rs

@@ -431,7 +431,7 @@ pub(crate) fn blueprint_slot_prose(doc: &str, env: &crate::project::Env) -> Resu
 /// envelope (a JSON object: `format_version` + `blueprint`) OR a construction
 /// op-list (a JSON array) — shape-discriminated on the top-level JSON type,
 /// each canonicalized by its own rules.
-fn composite_from_any(text: &str, env: &crate::project::Env) -> Result<Composite, String> {
+pub(crate) fn composite_from_any(text: &str, env: &crate::project::Env) -> Result<Composite, String> {
     let value: serde_json::Value =
         serde_json::from_str(text).map_err(|e| format!("invalid document: {e}"))?;
     match value {