fix(audit-2026-06-11/F-SE-H-04): scrub runtime error detail from public data-plane responses

ExecError::Runtime strings (filesystem paths, "blocked by SSRF policy:
link-local" cloud-metadata reconnaissance, pool-exhaustion timing,
panic fragments, and attacker-thrown strings) were returned verbatim in
the public /api/v1/execute + user-route 502 bodies. This handler only
serves anonymous data-plane callers (the authenticated script-test path
is in manager-core and keeps verbose errors), so log the full text
server-side under a correlation id and return a stable generic message
plus the id for operator grep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/orchestrator-core/src/api.rs

@@ -750,7 +750,31 @@ impl IntoResponse for ApiError {
                 ExecError::OperationBudgetExceeded => {
                     (StatusCode::INSUFFICIENT_STORAGE, e.to_string())
                 }
-                ExecError::Runtime(_) => (StatusCode::BAD_GATEWAY, e.to_string()),
+                ExecError::Runtime(detail) => {
+                    // Audit 2026-06-11 (F-SE-H-04) — runtime / SDK error
+                    // strings leak internal detail to the public data
+                    // plane: filesystem paths, "blocked by SSRF policy:
+                    // link-local" (confirms cloud-metadata reachability),
+                    // pool-exhaustion timing, and panic/backtrace
+                    // fragments. They also reflect attacker-thrown
+                    // strings (`throw "..."`) back into operator-facing
+                    // JSON. This handler only ever serves anonymous
+                    // data-plane callers (execute-by-id + user routes;
+                    // the authenticated script-test path lives in
+                    // manager-core and keeps verbose errors), so log the
+                    // full text server-side under a correlation id and
+                    // return only a stable generic message + the id.
+                    let correlation_id = Uuid::new_v4();
+                    tracing::warn!(
+                        %correlation_id,
+                        detail = %detail,
+                        "script runtime error (detail scrubbed from response)"
+                    );
+                    (
+                        StatusCode::BAD_GATEWAY,
+                        format!("script execution error (ref: {correlation_id})"),
+                    )
+                }
                 ExecError::Overloaded { .. } => unreachable!("handled above"),
             },
         };