✨ Implement leadership-based permissions for Meetup management

- 🔒 Restrict event creation, editing, and deletion to Meetup leaders (`is_leader`) and creators for consistency across APIs, frontend, and MCP.
- ➕ Add new APIs for leader delegation: assign/remove Meetup leaders via `meetup_user.is_leader`.
- 🛠️ Replace loose member checks with specific leadership checks in policies, controllers, and views.
- 🧪 Add exhaustive tests to ensure only eligible leaders execute critical actions (e.g., event creation/edit, Meetup updates).
- 🔄 Refactor pivot relationships and models (`leadByMe`, `isLeader`) for explicit leadership handling.
- ✨ Introduce artisan command `meetups:promote-existing-leaders` to transition legacy data.

tests/Feature/Meetups/CreateMeetupEventSeriesTest.php

@@ -6,8 +6,8 @@ use App\Models\MeetupEvent;
 use Livewire\Livewire;
 
 it('creates a weekly series via the web editor using the shared action', function () {
-    actingAsUser();
-    $meetup = Meetup::factory()->create();
+    // Termin-Verwaltung erfordert Leaderschaft; Ersteller ist per Hook Leader.
+    $meetup = Meetup::factory()->create(['created_by' => actingAsUser()->id]);
 
     Livewire::test('meetups.create-edit-events', ['meetup' => $meetup])
         ->set('seriesMode', true)
@@ -22,15 +22,15 @@ it('creates a weekly series via the web editor using the shared action', functio
         ->assertHasNoErrors()
         ->assertRedirect();
 
-    // The web editor parses the end date at midnight, so the occurrence on the end
-    // date's evening falls outside the range: 2026-07-01, 07-08, 07-15, 07-22 = 4.
-    // The shared action yields the identical result for the same inputs.
-    expect(MeetupEvent::where('meetup_id', $meetup->id)->count())->toBe(4);
+    // Das Enddatum aus dem Datums-Picker gilt inklusiv bis zum Tagesende
+    // (endOfDay), daher ist das Vorkommen am Enddatum-Abend dabei:
+    // 2026-07-01, 07-08, 07-15, 07-22, 07-29 = 5. Deterministisch, unabhängig
+    // von der Laufzeit-Uhrzeit.
+    expect(MeetupEvent::where('meetup_id', $meetup->id)->count())->toBe(5);
 });
 
 it('previews the same dates it will create', function () {
-    actingAsUser();
-    $meetup = Meetup::factory()->create();
+    $meetup = Meetup::factory()->create(['created_by' => actingAsUser()->id]);
 
     Livewire::test('meetups.create-edit-events', ['meetup' => $meetup])
         ->set('seriesMode', true)
@@ -38,5 +38,5 @@ it('previews the same dates it will create', function () {
         ->set('startTime', '18:00')
         ->set('endDate', '2026-07-29')
         ->set('recurrenceType', RecurrenceType::Weekly->value)
-        ->assertSet('previewDates', fn ($dates) => count($dates) === 4);
+        ->assertSet('previewDates', fn ($dates) => count($dates) === 5);
 });

tests/Feature/Meetups/EditMeetupTest.php

@@ -63,23 +63,38 @@ it('allows update when name is unchanged (Rule::unique ignores own id)', functio
         ->assertHasNoErrors();
 });
 
-it('allows updateMeetup for a member of the meetup_user pivot who is not the creator', function () {
+it('allows updateMeetup for a delegated leader who is not the creator', function () {
+    $leader = actingAsUser();
+    $meetup = Meetup::factory()->create([
+        'city_id' => $this->city->id,
+        'name' => 'Original Name',
+        'created_by' => User::factory()->create()->id,
+    ]);
+    $meetup->users()->attach($leader, ['is_leader' => true]);
+
+    Livewire::test('meetups.edit', ['meetup' => $meetup])
+        ->set('name', 'Updated By Leader')
+        ->set('city_id', $this->city->id)
+        ->set('community', 'einundzwanzig')
+        ->call('updateMeetup')
+        ->assertHasNoErrors();
+
+    expect($meetup->refresh()->name)->toBe('Updated By Leader');
+});
+
+it('blocks updateMeetup for a plain member (is_leader = false) who is not the creator', function () {
     $member = actingAsUser();
     $meetup = Meetup::factory()->create([
         'city_id' => $this->city->id,
         'name' => 'Original Name',
         'created_by' => User::factory()->create()->id,
     ]);
-    $meetup->users()->attach($member);
+    $meetup->users()->attach($member, ['is_leader' => false]);
 
     Livewire::test('meetups.edit', ['meetup' => $meetup])
-        ->set('name', 'Updated By Member')
-        ->set('city_id', $this->city->id)
-        ->set('community', 'einundzwanzig')
-        ->call('updateMeetup')
-        ->assertHasNoErrors();
+        ->assertStatus(403);
 
-    expect($meetup->refresh()->name)->toBe('Updated By Member');
+    expect($meetup->refresh()->name)->toBe('Original Name');
 });
 
 it('blocks updateMeetup when the user is neither creator nor pivot member', function () {

tests/Feature/Meetups/ManageEventsAuthTest.php

@@ -0,0 +1,29 @@
+<?php
+
+use App\Models\Meetup;
+use App\Models\User;
+use Livewire\Livewire;
+
+it('lets a leader open the event editor', function () {
+    $meetup = Meetup::factory()->create(['created_by' => actingAsUser()->id]);
+
+    Livewire::test('meetups.create-edit-events', ['meetup' => $meetup])
+        ->assertOk();
+});
+
+it('blocks a non-leader member from the event editor', function () {
+    $member = actingAsUser();
+    $meetup = Meetup::factory()->create(['created_by' => User::factory()->create()->id]);
+    $meetup->addMember($member); // is_leader = false
+
+    Livewire::test('meetups.create-edit-events', ['meetup' => $meetup])
+        ->assertStatus(403);
+});
+
+it('blocks a stranger from the event editor', function () {
+    actingAsUser();
+    $meetup = Meetup::factory()->create(['created_by' => User::factory()->create()->id]);
+
+    Livewire::test('meetups.create-edit-events', ['meetup' => $meetup])
+        ->assertStatus(403);
+});