add unichain support

[YouStillAlive]

closes #69

[Copilot]

Pull Request Overview

This PR adds support for the Unichain network to the subgraph project by implementing build and deployment configurations. The addition enables the project to deploy subgraphs to Unichain alongside the existing Matic and Base networks.

• Adds Unichain network configuration with contract addresses and deployment scripts
• Updates CI/CD workflow to support Unichain deployments with proper authentication
• Includes comprehensive contract mapping for all provider types on the Unichain network

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
package.json	Adds build and deploy scripts for Unichain network and updates existing deploy script names
networks.json	Defines Unichain network configuration with contract addresses and start blocks for all providers
.github/workflows/deploy-subgraph.yml	Extends CI workflow to include Unichain as a deployment option with authentication setup

[Copilot]

Multiple providers use the zero address (0x0000000000000000000000000000000000000000) which typically indicates undeployed or placeholder contracts. Consider adding comments to clarify whether these are intentionally disabled or awaiting deployment.