Adds Cloud Signature Consortium (CSC) integration for AES/QES signing
against a configured TSP. v1 ships as instance-wide configuration via
environment variables, with per-envelope signature level selection,
license gating, and an OAuth-driven signing flow (capture + FIFO
signers, SAD session, blocking/in-progress recipient pages).
Includes signature level compatibility checks (role, signing order,
dictate next signer), envelope mutability assertions, Prisma migration
for signature level and CSC tables, and docs for the new signing
certificate options.
This PR is handles the changes required to support envelopes. The new
envelope editor/signing page will be hidden during release.
The core changes here is to migrate the documents and templates model to
a centralized envelopes model.
Even though Documents and Templates are removed, from the user
perspective they will still exist as we remap envelopes to documents and
templates.
Lucas Smith
David Nguyen
Ephraim Duncan