feat: implement governance monitoring framework

[SharifIbrahimDev]

Closes #146

Description

This PR implements the Governance Monitoring Framework to track governance-related blockchain events affecting protocol security.

Features

1. Governance Schema Models: Expanded prisma/schema.prisma with robust definitions for:
   • Proposal: Tracks the metadata and lifecycle of proposals.
   • Vote: Records specific voting parameters, including voter choice and weight.
   • GovernanceEvent: High-level event ledger mapped to transaction hashes.
2. Governance Module: Built a complete module under apps/backend/src/modules/governance/.
   • Dedicated service encapsulating Prisma operations for safe database ingestion and query.
   • Extensible REST controller ready to be connected to dashboards or polling workers.
3. Application Registration: GovernanceModule is fully wired into AppModule and passes backend build steps without issues.

The database changes have been generated via Prisma, and this modular structure will safely support expanding ingestion behaviors down the line.

[mijinummi]

LGTM!