Module context 

Procedure-context construction helper.

Collapses the ~25-line “build host + attach writer + read principal + construct context” block previously duplicated between the simple-executor and DataFusion-graph procedure-call paths in uni-query (see query/executor/procedure.rs and query/df_graph/procedure_call.rs).

Writer attachment varies between the two paths (from_components vs. from_graph_ctx_with_request plus a writer mutation on the concrete QueryProcedureHost), so it stays at the caller. This helper owns only the principal-attachment + context-build step, which is the piece that was textually identical at both sites.

Functions

build_procedure_context

Build a ProcedureContext wiring host and an optional principal.