feat: add vp value to leaderboard

[wa0x6e]

Toward https://github.com/snapshot-labs/workflow/issues/625
Depends on #566

This PR will add a new vp_value column to the leaderboard, tracking the user's total voting power value across spaces and proposals

Value will be updated on:

• vote creation
• proposal deletion

Test

Add the new column in the database

 -- Add vp_value column to leaderboard table
  ALTER TABLE leaderboard ADD COLUMN vp_value DECIMAL(13,3) NOT NULL DEFAULT 0.000;

  -- Add index for the new vp_value column for efficient queries
  ALTER TABLE leaderboard ADD INDEX vp_value (vp_value);

With a copy of the database with almost 10M of rows, this query is pretty fast, less than 10s

• vote on a proposal with value
• in the leadearboard tables, in the row corresponding to your address and space, you should see the vote value
• when voting on another proposal on the same space, this value should increment by the vote's value
• when deleting a proposal, the value should decrement by the vote's value

Notes

• This PR will only enable feature on future votes, a batch script to fill previous votes will come in a separate PR

[Copilot]

Pull Request Overview

This PR adds voting power value tracking to the leaderboard system by introducing a new vp_value column that accumulates the total voting power value for each user across spaces and proposals.

• Adds vp_value column to the leaderboard table schema with appropriate indexing
• Updates vote creation logic to increment the user's voting power value in the leaderboard
• Implements voting power value decrementation when proposals are deleted

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
test/schema.sql	Adds vp_value DECIMAL column and index to leaderboard table
src/writer/vote.ts	Updates vote creation to track and increment voting power values in leaderboard
src/writer/delete-proposal.ts	Implements batch processing to decrement voting power values when proposals are deleted
src/helpers/entityValue.ts	Refactors vote value calculation using reduce for better readability