feat: add change-server support for bitcoin, bitcoincash, dogecoin, litecoin

[bobbythelobster]

Integrate the change-server protocol for UTXO engines following the contract in edge-core-js PR #718.

Key Changes

• Upgrade edge-core-js to ^2.43.0 for change-server types
• Wire onSubscribeAddresses callback through EngineEmitter
• Add syncNetwork() to UtxoEngine for change-server wakeups
• Gate block-height confirmation checks behind usesChangeServer
• Set usesChangeServer: true for bitcoin, bitcoincash, dogecoin, litecoin

How It Works

When usesChangeServer is enabled:

• Engine subscribes wallet addresses with core via onSubscribeAddresses
• Core subscribes them on the change-server
• On address activity, core calls syncNetwork({ subscribeParam })
• Engine triggers address-scoped transaction + UTXO refresh (reusing existing processing)
• Block events no longer queue per-tx confirmation fetches (the key optimization)
• Unconfirmed→confirmed transitions discovered via address wakeups instead

When usesChangeServer is disabled:

• All existing Blockbook-driven behavior unchanged

Contract compliance (per edge-core-js PR #718)

• Set currencyInfo.usesChangeServer = true
• Accept subscribedAddresses from core
• Call onSubscribeAddresses() with wallet addresses on startup
• Implement syncNetwork() for change-server wakeups
• Keep ordinary Blockbook polling as fallback
• Handle needsSync === false
• Handle missing checkpoints
• seenTxCheckpoint already implemented

Relates to Asana task 1213394471711299