[Task]: Add Redis governance request persistence

[rian-be]

Summary

Add dedicated persistence layer for Redis backed governed mutation requests so request creation, optimistic-concurrency updates, and index maintenance are handled consistently.

Goal

Make Redis backed governance writes explicit and reusable by separating request persistence mechanics from higher level store orchestration while preserving governance revision semantics.

Scope

What should be implemented?

• Add ModularityKit.Mutator.Governance.Redis.Storage.Persistence area for Redis backed request writes
• Support request creation with an initial provider managed revision
• Support optimistic concurrency updates for governed requests
• Define persistence records for Redis document and revision writes
• Support reading the current stored request for update validation
• Support Redis transaction writing for create and update flows
• Support Redis secondary index maintenance during request writes
• Keep persistence mechanics internal to the Redis provider boundary

Acceptance Criteria

• Governed mutation requests can be created and updated through dedicated Redis persistence layer
• Redis-backed updates preserve expected revision semantics
• Persistence record construction is separated from transaction command writing
• Secondary-index maintenance is part of the Redis write path
• Higher level store services can reuse the same persistence path
• Persistence behavior remains aligned with Redis keyspace, serialization, and concurrency decisions

Notes

Redis backed governance writes need more than simple document replacement. Request revisions, secondary indexes, and durable request documents need to move together so lifecycle and approval data stay coherent after updates.

This should align with the Redis provider storage, concurrency, and compatibility ADRs.

Related ADRs:

• ADR-029: Governance Redis Provider Package
• ADR-030: Governance Redis Request Storage and Query Strategy
• ADR-031: Governance Redis Serialization and Document Compatibility
• ADR-032: Governance Redis Concurrency and Index Maintenance Model