Index Treasury Governor voting behavior for governance transparency

[rickstaa]

Context

Governance voting data exists on-chain in LivepeerGovernor, but the subgraph does not currently expose per-voter voting state or proposal-level vote aggregates in a structured way. This makes it difficult for downstream consumers (Explore/UI, analytics, governance dashboards) to surface orchestrator voting behavior and proposal vote distributions.

A UI feature request (Explorer#310) depends on this data being available in the subgraph.

Goal

Extend the subgraph to fully index treasury governance voting by:

• Tracking per-proposal vote aggregates (for / against / abstain / total weight)
• Tracking per-voter voting state on each proposal
• Emitting vote event entities for historical and timeline-based views

This data should enable:

• Orchestrator voting history views
• Proposal-level breakdowns of how orchestrators voted
• Lightweight governance participation metrics in the UI

Scope

• Index VoteCast and VoteCastWithParams events from LivepeerGovernor
• Introduce entities such as:
  • TreasuryVote (proposal × voter state)
  • TreasuryVoteEvent (event-level history)
• Maintain accurate proposal-level vote tallies

Dependency

Blocks UI work in Explore (Feature #310 / #457).