Feat/pd 4401 stack upgrade

[hieu-w]

Motivation and Context

Jira Link:
https://toruslabs.atlassian.net/browse/PD-4320

Description

Stack upgrade:

• Update deps
• Eslint 9 flat config
• Migrate mocha+chai -> vitest
• CI node 22, node engine 20

How has this been tested?

• npm run test
• npm run build
• npm run lint

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project. (run lint)
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• My code requires a db migration.