Bootstrap DRDD module

[lowhung]

Context

The DRDD (DRep Delegation Distribution) State module tracks historical snapshots of governance delegation distributions across epochs. It subscribes to DRep distribution messages published by accounts state and stores them for historical queries.

Problem

When bootstrapping from a snapshot (e.g., epoch 500), the DRDD state module needs to initialize with the current DRep delegation distribution rather than waiting for the first epoch transition after bootstrap to receive distribution data.

Acceptance Criteria

• DRDD state initializes from snapshot data during bootstrap
• Current epoch's DRep distribution loaded from snapshot
• Historical distribution tracking works after bootstrap (i.e we can resume from either Mithril or Upstream / Peer Networking once bootstrap is done)
• Normal distribution updates continue after bootstrap

Testing Requirements

• Bootstrap from fixture snapshot initializes DRDD correctly
• DRep distribution queries return correct data after bootstrap

Definition of Done

• DRDD state initializes from snapshot without waiting for epoch transition
• Current DRep distribution available after bootstrap
• Historical tracking continues normally after bootstrap