Opening Journal Render

Render the edited opening-entry document to a file + write a render-audit row.

Accountant/owner (ZCT-257). Its preview/render siblings in journal_export are deliberately member-level because they persist nothing; this one does not qualify — it writes an :class:OpeningEntryRenderAudit row carrying caller-supplied content (was_edited, the rendered sha256, the actor). A route that stores what the caller sent is a create, and under the ruling a member creates nothing.

pid not owned by {cid} → 404. Reloads the target-FY chart, runs the fixed render pipeline + validation (posting dates constrained to target_fiscal_year → 422 on a cross-FY/unbalanced/out-of-chart document), renders format → file bytes, and writes one :class:OpeningEntryRenderAudit row (company_id from the loaded proposal, was_edited = whether the request diverges from the stored proposal, rendered_sha256 of the bytes, generated_by = current user). The legacy GET .../file stays read-only and unaudited.