Extract engine command and state helpers

crates/engine/src/cmd/variablecmds/csv.rs

@@ -1,4 +1,7 @@
-use super::*;
+use super::{
+    BTreeMap, BTreeSet, DataSet, DataValue, EngineError, MAX_NAME, Result, Session, Value, Variable, VariableKind, Variables, absolute_path, bad,
+    json, read_file_head, str_param, variables_unlocked, write_file,
+};
 
 /// Cap on a graph variable's CSV (MCP and files are untrusted).
 pub(super) const MAX_GRAPH_CSV: usize = 256 * 1024;

crates/engine/src/cmd/variablecmds/library.rs

@@ -1,4 +1,7 @@
-use super::*;
+use super::{
+    BTreeMap, BTreeSet, DataSet, DataValue, EngineError, MAX_NAME, Result, Session, Value, Variable, VariableKind, absolute_path, bad, json, named,
+    read_file_head, str_param, variables_unlocked,
+};
 
 /// Caps on a variable library (paths and MCP payloads are untrusted): its size, its XML nodes, how
 /// deep its elements nest, and the entities, variables and data sets it declares.