research: encryption at rest for Ruflo data #402

Why

ADR-0059 is cited but has no file (remediation v2 D-11).

In scope

Intake: where Ruflo data lives after P2 and what encryption would protect.

Out of scope

Implementation.

Acceptance criteria

• Problem, outcome and size range recorded

Dependencies

Blocked by: #340

Blocks: None

Plan

• Release: 4.1.0
• Size: size:M · Workstream: ws:capability
• Card: C41-02 in the card inventory
• Sources: Supersession ledger (docs(plans): v4 GA master plan, supersession ledger and v5 registers #290) D-11

Verification

Each acceptance criterion is checked on the pull request.