Uncommitted fork() should not affect $effect.pending() #18649

Describe the bug

I don't know if it's a bug or intentional, but the $effect.pending() rune is affected by promises created via fork(), even if it hasn't been committed.

This causes issues when using $effect.pending() to display a loading state.

I think $effect.pending() should not be affected by fork(), just like $state.eager().

Reproduction

https://svelte.dev/playground/cbfae12100cb456a8d466eb979e91957?version=5.56.9

• Click "increment" to start loading the data asynchronously.
  The UI is correctly updated to a loading state, thanks to $effect.pending(), and the DOM is updated when the promise resolve.

• Click "fork" to start loading the data asynchronously without updating the DOM, using fork().
  The DOM will not be updated until the fork is committed, except for $effect.pending() which will put the UI into an unwanted loading state.

Logs

REPL

System Info

REPL

Severity

annoyance