[Deliverable] Allow multiple RLN provers to share a database

[jm-clius]

Owner: AnonComms Zerokit-RLN

FURPS:

• F1. The RLN prover module supports gasless L2 operations
• F2. Multiple RLN prover instances can operate on a shared database
• U4. The RLN prover module has an associated specification
• R1. Multiple RLN prover instances operate consistently without database conflicts

Checklist:

• Specs: link to specs and/or API definition
• Code: link to GitHub issues/PRs/Epic
• Dogfood: link to dogfooding session/artefact
• Docs: links to README.md or other docs