* Part 2 of eslint prefer-const

* Release notes

* Update

~based on #1114~

This brings its build process up to date with the rest of the project.
We can now use Node 20 to build successfully.

Closes #918

<!-- Thank you for submitting a pull request! Make sure to follow the
instructions to write release notes for your PR — it should only take a
minute or two:
https://github.com/actualbudget/docs#writing-good-release-notes -->

* Make it easier to build the bundle.api.js for the API

* Remove budgetId parameter, move config to top level of API

* that’s a breaking change

* Add support for signing into the server in init()

* Add api.downloadBudget(syncId, { password }) method

* Fix lint errors

* Refactor: extract out getSyncError

* api/download-budget: sync if possible instead of downloading

* Don’t bother with fetching remote files and installing key if the file is local

* *groupId

* FIx lint issues

* Remove extra close+reopen

* Refactor out duplicate load-budget logic

* Trailing commas