Implemented Folia-safe sign check for teleportation in front instead on top

[nezbite]

Summary

What does this PR do?

Teleportation checks sign location of shop and teleports the player there when using /qs browse

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Type of Change

• Feature
• Bug fix
• Refactor / Cleanup
• Documentation
• Breaking change

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Basic Checks

• I have tested these changes locally
• I confirm no undocumented AI-generated code was used in this submission

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Notes (optional)

Add anything important for reviewers:

• Teleportation on top does not check for safety, neither does this one, but the chance of it being safe will be greater because of how shops are created with this plugin in general.
• Double-chest shops need testing

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Breaking Changes (if applicable)

• What changed: Teleport location changed. Could influence users of shops that only know this behaviour.

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[CLAassistant]

All committers have signed the CLA.

[nezbite]

Double-chest shops have been tested and work as intended.

[Warriorrrr]

This doesn't seem thread safe to me, accessing the world state (either directly via Block#getState or via the getSigns method) is explicitly what that note is warning you about, there's no guarantee you're currently on the right region thread for the shop.

A better way to do this would be to only start looking for the teleport location once the teleport action is used and after the inventory is closed, schedule a task on the region thread for the shop that then schedules an async chunk load. Only then can you safely call Shop#getSigns to try and find a valid teleport location.

[creatorfromhell]

I'm going to withhold this until the API expansion PR, but as stated above, it mixes world interaction where it shouldn't