Chore: Sync fuzzer: Add new possible actions: Adding and syncing a new temporary client on an existing account

[personalizedrefrigerator]

Summary

This pull request adds actions to the sync fuzzer that allow:

• Adding a new client on the same account as an existing client.
  • Before the first sync, the new client is usually initialized with a new folder and a number of initial notes.
• Removing an added client.

Additionally, to debug issues experienced while working on this pull request, it:

• Adds additional debug logic.
• Adjusts how commands are run.
  • Previously, commands were run with something similar to "yarn start-no-build --profile=... command-here args-here". This created one CLI process per command.
  • The web clipper API server was started just like any other command. However, the API server ran until a client was closed. As a result, it was possible for multiple same-profile CLI processes to be running at the same time.
  • This pull request adjusts the batch CLI command to allow accepting input from process.stdin when ran with - as the filename. The fuzzer uses batch - to send commands to the same CLI process. This allows the web clipper API server to run in the same process as normal CLI commands.

Tasks

• Move debugging-related changes to a separate pull request.
• Currently, the sync fuzzer randomly fails with an E2EE sync-related error. Interestingly, this issue occurs at different points even with a constant seed.
  • Current workaround: Repeatedly resync after a delay when a sync fails.
• Fix a conflict-related sync issue — either adjust the fuzzer's expected state or fix the sync bug.
  • The conflict issue seems to also be encountered by the existing fuzzer logic in dev.