Add cross-references between the two preamble execution paths

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: teunbrand

src/execute/cte.rs

@@ -243,9 +243,10 @@ pub fn transform_global_sql(
     // VISUALISE FROM. Split them: side-effect statements run directly,
     // VISUALISE FROM becomes the queryable part.
     //
-    // Only actual statements (CREATE, INSERT, …) are side effects — a bare
-    // WITH clause without a trailing statement is not executable on its own
-    // (its CTEs are already materialized separately).
+    // Only structured DML is handled here — other_sql_statement nodes
+    // (INSTALL, LOAD, SET, …) are pre-executed in prepare_data_with_reader.
+    // A bare WITH clause without a trailing statement is not executable on
+    // its own (its CTEs are already materialized separately).
     let root = source_tree.root();
 
     let side_effect_stmts = r#"

src/execute/mod.rs

@@ -1043,7 +1043,9 @@ pub fn prepare_data_with_reader(query: &str, reader: &dyn Reader) -> Result<Prep
         ));
     }
 
-    // Execute setup statements (INSTALL, LOAD, SET, etc.) before the main query
+    // Execute setup statements (INSTALL, LOAD, SET, etc.) before the main query.
+    // Structured DML (CREATE, INSERT, UPDATE, DELETE) is handled separately as
+    // side-effects in cte::transform_global_sql.
     for stmt in source_tree.find_texts(&root, "(sql_statement (other_sql_statement) @stmt)") {
         execute_query(&stmt)?;
     }