Complete a Document File Upload

Body for complete-document-upload: store the uploaded file as a document.

Uniform response shape for every operation endpoint.

Every dispatch carries an op_<ULID> operation_id, which is the bridge to the monitoring surface: pass it to GET /v1/operations/{operation_id}/stream (see routers/operations.py) to subscribe to SSE progress events. Sync commands complete in the envelope itself (status: "completed", HTTP 200); async commands (status: "pending", HTTP 202) hand off to a background worker and stream their tail through that SSE endpoint. Failed dispatches still mint an operation_id so the audit log and any partial SSE events stay correlatable.

TResult parameterizes result so per-op response shapes surface in OpenAPI. Operations that pin OperationSpec.result_type get OperationEnvelope[YourEnvelope] as their response model; the rest keep the default Any shape (result: any | null on the wire).