fix: Modify Popup.svelte to accept slots to render header and footer …

[fcrespo82]

Summary

This PR improves how popup windows are displayed across the app, especially in places like Settings, Plugins, Profile management, and Plugin details.

Previously, popup content could behave awkwardly when there was too much information on screen. Titles, close buttons, and footer content could scroll together with the rest of the popup, and in some cases footer text could overlap or sit on top of the main content.

With this change, popups have clearer sections: the top area stays reserved for the title and close button, the main content scrolls independently, and optional footer content stays separated from the scrollable area. This makes the popup layout more predictable and keeps important controls in a consistent place.

This does not add new user-facing features, but it improves the overall usability and polish of existing dialogs.

What Changed

• Improved popup layout so headers, content, and footers are handled separately.
• Updated Settings, Plugins, Profile Manager, Application Profiles, and Plugin Details popups to use the improved popup structure.
• Fixed the Settings footer so it no longer overlaps the main settings content.
• Made long popup content easier to scroll without losing the title or close button area.
• Preserved the existing visual style while making popup behavior more consistent.

Images

The settings one was taken with the inspector open to force the size to be able to see the difference.

Before	After

Preflight checklist

If you remove this checklist, this pull request will be closed without explanation.

• I understand that if this pull request is about support for non-Elgato or non-Tacto hardware, it will be closed without explanation, as per issue Statement regarding device support #38.
• I certify the compliance of this pull request with the Jellyfin LLM/"AI" Development Policy adopted by the OpenDeck project.
• I thoroughly understand the changes that I am proposing in this pull request, and I will be able to respond to questions and review feedback.
• I reasonably believe that the changes that I am proposing are of production quality, or I am otherwise opening this pull request as a draft.
• I have thoroughly reviewed the diff of my changes and ensured that I have neither introduced any unrelated additions, nor differences in unmodified code.
• I have ensured that I have run the appropriate formatter on my changes and that my code produces no linter violations.
• I will keep "Allow edits from maintainers" enabled for this pull request.

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[CLAassistant]

All committers have signed the CLA.

[Terrorwolf01]

May I ask what your Reasoning is to change this Behaviour?

[nekename]

Yeah, the changes look OK, but you need to provide a longer description of the change

[fcrespo82]

Sorry for the low effort on the original description. I made it late at night and forgot to add the description. I've updated the original description for the PR.

[Terrorwolf01]

Sorry for the low effort on the original description. I made it late at night and forgot to add the description. I've updated the original description for the PR.

Could you please also add some before, after Pictures?

[nekename]

Thanks, looks good! I'll look at this when I get back to OpenDeck stuff (who knows when)