fix: user group assignment options, details panel alignment

[JammingBen]

Only show relevant groups in user-group assignment. For removing groups, only show groups the user(s) are assigned to. For adding groups for one user, only show groups the uses is not already assigned to. For multiple users, we just show all groups because computing the intersection feels a bit overkill.

Also fixes the alignment in the user details panel and refactors some components to script setup.

fixes #1181

[Copilot]

Pull Request Overview

This pull request improves user group assignment functionality by showing only relevant groups in modals and fixes UI alignment issues. The changes enhance user experience by filtering available groups based on current assignments and refactor components to use Vue 3's composition API.

• Filters group options in add/remove modals to show only relevant groups
• Fixes alignment issues in the user details panel
• Refactors components from Options API to Composition API (script setup)

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
useUserActionsRemoveFromGroups.spec.ts	Updates test cases to verify visibility only when users have group memberships
DetailsPanel.spec.ts	Updates tests to check DOM elements instead of component properties after refactoring
RemoveFromGroupsModal.spec.ts	Adds tests for filtered group options and updates existing tests for component changes
AddToGroupsModal.spec.ts	Adds comprehensive tests for group filtering logic across different scenarios
useUserActionsRemoveFromGroups.ts	Adds logic to hide action when no users have group memberships
DetailsPanel.vue	Refactors to script setup and fixes alignment in multiple users view
RemoveFromGroupsModal.vue	Refactors to script setup and adds filtering to show only assigned groups
AddToGroupsModal.vue	Refactors to script setup and adds filtering to show only unassigned groups for single user

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