chore(deps): upgrade CI actions and Node test dependencies

[darioAnongba]

Summary

Periodic dependency audit and upgrade. All Cargo dependencies are already at their latest stable versions, so this PR focuses on CI actions and Node test dependencies.

CI Actions (major upgrades)

Action	Old	New
actions/checkout	v4.3.1	v6.0.2
actions/setup-node	v4.4.0	v6.2.0
actions/cache	v4 (unpinned)	v5.0.3 (SHA-pinned)

All actions in publish-release.yml are now SHA-pinned with version comments (previously only build-lint-test.yml was pinned).

Node Test Dependencies (major upgrades)

Package	Old	New
jest	^29.7.0	^30.2.0
@types/jest	^29.5.14	^30.0.0
eslint	^9.39.3	^10.0.2
eslint-plugin-jest	^28.14.0	^29.15.0
globals	^16.5.0	^17.3.0

Cargo Dependencies (no changes needed)

All at latest stable:

• wasm-bindgen 0.2.113, serde 1.0.228, anyhow 1.0.102
• bdk_wallet 2.3.0, bdk_esplora 0.22.1, bitcoin 0.32.8
• getrandom kept at 0.2.x (0.3+/0.4+ changed WASM approach; BDK's dependency tree needs 0.2.x with js feature)

Notes

• Jest 30 removes deprecated matcher aliases (e.g. toBeCalled → toHaveBeenCalled). Verified none are used in our tests.
• ESLint 10 breaking changes are minimal (formatter internals). Our flat config is compatible.
• ts-jest 29.4.6 supports Jest 30 via peer dependency range.
• yarn.lock will be updated by CI (yarn install --immutable will fail on first run — need to regenerate lockfile).

Ref #24