Add JUnit 5 tests for IslandTeamInviteGUI

[tastybento]

Summary

• Adds IslandTeamInviteGUITest with 23 JUnit 5 tests for IslandTeamInviteGUI
• Extends RanksManagerTestSetup and uses MockBukkit for the server mock
• Copies panel YAML files to a per-test temp directory so TemplateReader loads real templates

Test coverage

Category	Tests
Constructor	File exists → no saveResource; file missing → saveResource called
build()	Opens inventory; blank prospects with no players; click handler present for visible player; no handler for already-invited player; search name filters prospects by prefix
Pagination	NEXT/PREVIOUS shown/hidden correctly; clicking NEXT advances page and reveals PREVIOUS; clicking PREVIOUS decrements page
BACK button	inviteCmd=true closes inventory; inviteCmd=false also closes inventory
Prospect click handlers	LEFT→invite (success + failure); RIGHT→coop; SHIFT_LEFT→trust; unknown click type ignored
InviteNamePrompt	getPromptText returns translation; success ends conversation without rebuild; failed canExecute/execute schedules rebuild

Test plan

• All 23 tests pass locally (./gradlew test --tests "...IslandTeamInviteGUITest")

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
21 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud