Ledger Wallet Provider staging environment and v2 migration updates
Ledger Wallet Provider now supports `environment: 'staging'` for testing against Ledger pre-production wallet services, CAL and Ledger Sync. The configuration reference includes the available endpoints and a setup example. The 1.x.x to 2.0.0 migration guide has also been updated for the released v2 API, where integrations explicitly register the blockchain families they support.