test(wallet): cover address lifecycle and fee introspection APIs

[darioAnongba]

Summary

• strengthen Node-side wallet lifecycle coverage around revealed and unused addresses
• assert wallet-owned script detection and scanned output/UTXO lookup behavior after sync
• verify wallet fee and fee-rate helpers against a signed transaction in the funded integration flow
• add the required CHANGELOG entry under Unreleased

Testing

• cd tests/node && corepack yarn lint integration/wallet.test.ts integration/esplora.test.ts
• local wasm-pack build could not run on this host because clang is not installed for the wasm32-unknown-unknown target, so CI is the authoritative build/test check for this PR

Partially addresses #22.