Improve UX of join requests and fix minor bugs (#492)

## Description of the implemented changes
The changes were:
- [x] Bugfixing
- [x] New Feature
- [ ] Breaking Change
- [ ] Refactoring

This PR improves the join-request flow and presentation quality, fixes several data-display issues in join/join-request screens, and adds a usability improvement in global settings (directly opening the join link). It also includes dependency updates and changelog maintenance.

## What has been changed?
- Join form (`JoinLive`) now renders inputs based on actual field types (including checkbox/date/number/email behavior instead of generic text-only handling).
- Join form custom-field labels are resolved from configured custom fields (fallback remains safe if lookup fails).
- Join-request details page (`JoinRequestLive.Show`) now:
  - resolves and shows custom field names instead of raw IDs,
  - formats boolean-like values (`on/true/1`, `off/false/0`) as localized `Yes/No`,
  - formats ISO date strings for better readability,
  - keeps legacy field handling while improving output consistency.
- Join-request detail layout was improved semantically and visually (`dl/dt/dd` structure for label/value rows).
- Global settings page now includes an **Open** button for the join URL (`target="_blank"`, `rel="noopener noreferrer"`, ARIA label).
- Added/updated tests around:
  - join field type rendering,
  - custom field labels in join-request views,
  - related auth/global-settings behavior.
- Updated translations (`default.pot`, `en`, `de`) for new UI strings.
- Updated dependencies/tooling (`mix.lock`, `mix.exs`, CI/renovate-related updates).
- Updated `CHANGELOG.md` entries for unreleased changes.

## Definition of Done
### Code Quality
- [x] No new technical depths
- [x] Linting passed
- [x] Documentation is added were needed

### Accessibility
- [x] New elements are properly defined with html-tags
- [x] Colour contrast follows WCAG criteria
- [x] Aria labels are added when needed
- [x] Everything is accessible by keyboard
- [x] Tab-Order is comprehensible
- [x] All interactive elements have a visible focus

### Testing
- [x] Tests for new code are written
- [ ] All tests pass
- [ ] axe-core dev tools show no critical or major issues

## Additional Notes
- Reviewer focus areas:
  - `lib/mv_web/live/join_live.ex`: input type derivation and custom field lookup strategy (`authorize?: false` read path used intentionally for field metadata).
  - `lib/mv_web/live/join_request_live/show.ex`: value-formatting logic (especially backward compatibility for legacy `form_data` payloads).
  - `lib/mv_web/live/global_settings_live.ex`: external-link behavior and accessibility attributes.
- The branch also contains dependency update commits; please review lockfile and CI-related changes separately from functional join/join-request changes.

Reviewed-on: #492
Co-authored-by: Simon <s.thiessen@local-it.org>
Co-committed-by: Simon <s.thiessen@local-it.org>

test/membership/member_groups_relationship_test.exs

@@ -16,9 +16,13 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
 
   describe "Relationships" do
     test "member has many_to_many groups relationship (load with preloading)", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group1} = Membership.create_group(%{name: "Group One"}, actor: actor)
-      {:ok, group2} = Membership.create_group(%{name: "Group Two"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group1} =
+        Membership.create_group(%{name: unique_group_name("Group One")}, actor: actor)
+
+      {:ok, group2} =
+        Membership.create_group(%{name: unique_group_name("Group Two")}, actor: actor)
 
       {:ok, _mg1} =
         Membership.create_member_group(%{member_id: member.id, group_id: group1.id},
@@ -40,9 +44,11 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
     end
 
     test "load multiple members with groups preloaded (N+1 prevention)", %{actor: actor} do
-      {:ok, member1} = Membership.create_member(%{email: "member1@test.com"}, actor: actor)
-      {:ok, member2} = Membership.create_member(%{email: "member2@test.com"}, actor: actor)
-      {:ok, group} = Membership.create_group(%{name: "Test Group"}, actor: actor)
+      {:ok, member1} = Membership.create_member(%{email: unique_email("member1")}, actor: actor)
+      {:ok, member2} = Membership.create_member(%{email: unique_email("member2")}, actor: actor)
+
+      {:ok, group} =
+        Membership.create_group(%{name: unique_group_name("Test Group")}, actor: actor)
 
       {:ok, _mg1} =
         Membership.create_member_group(%{member_id: member1.id, group_id: group.id},
@@ -70,8 +76,10 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
 
   describe "Member-Group Association Operations" do
     test "add member to group via Ash API", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group} = Membership.create_group(%{name: "Test Group"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group} =
+        Membership.create_group(%{name: unique_group_name("Test Group")}, actor: actor)
 
       assert {:ok, member_group} =
                Membership.create_member_group(%{member_id: member.id, group_id: group.id},
@@ -83,8 +91,10 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
     end
 
     test "remove member from group via Ash API", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group} = Membership.create_group(%{name: "Test Group"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group} =
+        Membership.create_group(%{name: unique_group_name("Test Group")}, actor: actor)
 
       {:ok, member_group} =
         Membership.create_member_group(%{member_id: member.id, group_id: group.id},
@@ -107,10 +117,16 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
     end
 
     test "add member to multiple groups in single operation", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group1} = Membership.create_group(%{name: "Group One"}, actor: actor)
-      {:ok, group2} = Membership.create_group(%{name: "Group Two"}, actor: actor)
-      {:ok, group3} = Membership.create_group(%{name: "Group Three"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group1} =
+        Membership.create_group(%{name: unique_group_name("Group One")}, actor: actor)
+
+      {:ok, group2} =
+        Membership.create_group(%{name: unique_group_name("Group Two")}, actor: actor)
+
+      {:ok, group3} =
+        Membership.create_group(%{name: unique_group_name("Group Three")}, actor: actor)
 
       # Add to all groups
       {:ok, _mg1} =
@@ -138,8 +154,10 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
 
   describe "Edge Cases" do
     test "adding member to same group twice fails (duplicate prevention)", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group} = Membership.create_group(%{name: "Test Group"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group} =
+        Membership.create_group(%{name: unique_group_name("Test Group")}, actor: actor)
 
       {:ok, _mg1} =
         Membership.create_member_group(%{member_id: member.id, group_id: group.id},
@@ -154,8 +172,10 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
     end
 
     test "removing member from group they're not in (idempotent, no error)", %{actor: actor} do
-      {:ok, member} = Membership.create_member(%{email: "test@test.com"}, actor: actor)
-      {:ok, group} = Membership.create_group(%{name: "Test Group"}, actor: actor)
+      {:ok, member} = Membership.create_member(%{email: unique_email("member")}, actor: actor)
+
+      {:ok, group} =
+        Membership.create_group(%{name: unique_group_name("Test Group")}, actor: actor)
 
       # Verify no association exists
       {:ok, nil} =
@@ -194,4 +214,12 @@ defmodule Mv.Membership.MemberGroupsRelationshipTest do
       assert result == :ok || match?({:error, _}, result)
     end
   end
+
+  defp unique_email(prefix) do
+    "#{prefix}-#{System.unique_integer([:positive])}@test.com"
+  end
+
+  defp unique_group_name(prefix) do
+    "#{prefix} #{System.unique_integer([:positive])}"
+  end
 end