fix popover effect when host is not connected to the document

[ocavue]

In the updated $effect callback, if el isn't found during the initial render, this $effect won't trigger the isVisible rune. Even if el becomes available later, this effect won't be activated again when isVisible changes.

Why isn't el found during the first render? In our scenario, prosemirror-adapter dynamically mounts the Svelte component into a div element that isn't controlled by Svelte. When the Svelte component is mounted, $effect will be called, but the host div element isn't yet connected to the document, so document.getElementById() will return nothing. This issue was first reported in prosekit/prosemirror-adapter#163.

Minimal reproduction for this issue:

https://github.com/ocavue/meltui-pm-adapter-modal-issue

Clicking the first button should display the popover content.

Before:

m-before.mp4

After:

m-after.mp4

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Latest commit: c27c845

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Project	Deployment	Preview	Comments	Updated (UTC)
next-gen	Ready	Preview	Comment	Sep 4, 2025 7:23am