Sync v2 performance, initial sync limit=1

[t3chguy]

Known issues:

1. Only ensures a minimum of a single previewable event has been fetched rather than a handful (e.g. 5-10)
2. Doesn't apply any smart sorting as to what order to load them in (e.g. visible first)
3. Doesn't persist work, as js-sdk only persists accumulated sync responses, meaning that on refresh all this data will need re-fetching.
4. No unit tests

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Here's what your changelog entry will look like:

✨ Features

• Sync v2 performance, initial sync limit=1 (#9299).