refactor: Define CTE-related SQL nodes for emitter

bigframes/core/compile/sqlglot/compiler.py

@@ -62,6 +62,8 @@ def compile_sql(request: configs.CompileRequest) -> configs.CompileResult:
     if request.sort_rows:
         result_node = typing.cast(nodes.ResultNode, rewrite.column_pruning(result_node))
         encoded_type_refs = data_type_logger.encode_type_refs(result_node)
+        # TODO: Extract CTEs earlier
+        result_node = typing.cast(nodes.ResultNode, rewrite.extract_ctes(result_node))
         sql = _compile_result_node(result_node)
         return configs.CompileResult(
             sql,
@@ -74,6 +76,8 @@ def compile_sql(request: configs.CompileRequest) -> configs.CompileResult:
     result_node = dataclasses.replace(result_node, order_by=None)
     result_node = typing.cast(nodes.ResultNode, rewrite.column_pruning(result_node))
     encoded_type_refs = data_type_logger.encode_type_refs(result_node)
+    # TODO: Extract CTEs earlier
+    result_node = typing.cast(nodes.ResultNode, rewrite.extract_ctes(result_node))
     sql = _compile_result_node(result_node)
     # Return the ordering iff no extra columns are needed to define the row order
     if ordering is not None:
@@ -256,6 +260,23 @@ def compile_isin_join(
     )
 
 
+@_compile_node.register
+def compile_cte_ref_node(node: sql_nodes.SqlCteRefNode, child: sqlglot_ir.SQLGlotIR):
+    return sqlglot_ir.SQLGlotIR.from_cte_ref(
+        node.cte_name,
+        uid_gen=child.uid_gen,
+    )
+
+
+@_compile_node.register
+def compile_with_ctes_node(
+    node: sql_nodes.SqlWithCtesNode,
+    child: sqlglot_ir.SQLGlotIR,
+    *ctes: sqlglot_ir.SQLGlotIR,
+):
+    return child.with_ctes(tuple(zip(node.cte_names, ctes)))
+
+
 @_compile_node.register
 def compile_concat(
     node: nodes.ConcatNode, *children: sqlglot_ir.SQLGlotIR