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/main.rs

@@ -2730,12 +2730,7 @@ fn dispatch_graph(a: GraphCmd, env: &project::Env) {
                     eprintln!("aura: {path}: {e}");
                     std::process::exit(2);
                 });
-                let bp = blueprint_from_json(&doc, &|t| env.resolve(t)).unwrap_or_else(|e| {
-                    let mut msg = graph_construct::blueprint_load_prose(&e);
-                    if let Some(hint) = graph_construct::unresolved_namespace_hint(&e, env) {
-                        msg.push_str(" — ");
-                        msg.push_str(&hint);
-                    }
+                let bp = graph_construct::composite_from_any(&doc, env).unwrap_or_else(|msg| {
                     eprintln!("aura: {path}: {msg}");
                     std::process::exit(2);
                 });