fix: keep serialized remote data alive until navigation

[Rich-Harris]

This PR allows both of these remote function calls...

{#if await condition()}
  <h1>{await message()}</h1>
{/if}

...to use the data that was serialized when those queries were encountered during SSR. At present, only condition() is used, because started becomes true synchronously after the hydrate(...) call, before the contents of the if block are rendered.

The heuristic here (use the serialized data until navigation occurs) is 98% good enough, though in the long term it would be preferable to knit this stuff into the actual hydration process. That's a ways off though.

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[dummdidumm]

one code golf suggestion, otherwise 👍

[Rich-Harris]

converted this to draft as it doesn't currently handle myquery.refresh(), and while fixing that I uncovered what I think is a bug

[Rich-Harris]

Actually I take it back, not a bug. Just me holding it wrong