Allow editing an existing transaction

Desktop reuses the add-form with a Modifier link per row; mobile gets
a "Dernières opérations" list under the quick-entry form since no
table exists there.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/Feature/SuiviTest.php

@@ -2,6 +2,7 @@
 
 use App\Livewire\Suivi\Index;
 use App\Models\User;
+use Illuminate\Database\Eloquent\ModelNotFoundException;
 use Livewire\Livewire;
 
 it('records a transaction for the current household', function (): void {
@@ -98,6 +99,89 @@ it('resets the form to defaults after adding a transaction', function (): void {
     expect($component->get('details'))->toBe('');
 });
 
+it('prefills the form when starting to edit a transaction', function (): void {
+    $user = User::factory()->create();
+    $household = $user->currentHousehold;
+    $category = $household->categories()->create(['name' => 'Loyer', 'type' => 'depense', 'position' => 1]);
+    $transaction = $household->transactions()->create([
+        'category_id' => $category->id, 'user_id' => $user->id,
+        'date' => '2026-03-05', 'date_effective' => '2026-03-06', 'amount' => 1200, 'details' => 'Loyer mars',
+    ]);
+
+    $component = Livewire::actingAs($user)->test(Index::class)->call('startEditTransaction', $transaction->id);
+
+    expect($component->get('editingTransactionId'))->toBe($transaction->id);
+    expect($component->get('categoryId'))->toBe($category->id);
+    expect($component->get('amount'))->toBe('1200.00');
+    expect($component->get('details'))->toBe('Loyer mars');
+    expect($component->get('date'))->toBe('2026-03-05');
+    expect($component->get('dateEffective'))->toBe('2026-03-06');
+});
+
+it('updates an existing transaction instead of creating a new one', function (): void {
+    $user = User::factory()->create();
+    $household = $user->currentHousehold;
+    $category = $household->categories()->create(['name' => 'Loyer', 'type' => 'depense', 'position' => 1]);
+    $newCategory = $household->categories()->create(['name' => 'Courses', 'type' => 'depense', 'position' => 2]);
+    $transaction = $household->transactions()->create([
+        'category_id' => $category->id, 'user_id' => $user->id,
+        'date' => '2026-03-05', 'date_effective' => '2026-03-05', 'amount' => 1200, 'details' => 'Loyer',
+    ]);
+
+    Livewire::actingAs($user)
+        ->test(Index::class)
+        ->call('startEditTransaction', $transaction->id)
+        ->set('categoryId', $newCategory->id)
+        ->set('amount', '150')
+        ->set('details', 'Courses rectifiées')
+        ->call('addTransaction')
+        ->assertDispatched('transaction-updated');
+
+    expect($household->transactions()->count())->toBe(1);
+
+    $transaction->refresh();
+    expect($transaction->category_id)->toBe($newCategory->id);
+    expect((float) $transaction->amount)->toBe(150.0);
+    expect($transaction->details)->toBe('Courses rectifiées');
+});
+
+it('cancels editing and resets the form without touching the transaction', function (): void {
+    $user = User::factory()->create();
+    $household = $user->currentHousehold;
+    $category = $household->categories()->create(['name' => 'Loyer', 'type' => 'depense', 'position' => 1]);
+    $transaction = $household->transactions()->create([
+        'category_id' => $category->id, 'user_id' => $user->id,
+        'date' => '2026-03-05', 'date_effective' => '2026-03-05', 'amount' => 1200, 'details' => 'Loyer',
+    ]);
+
+    $component = Livewire::actingAs($user)
+        ->test(Index::class)
+        ->call('startEditTransaction', $transaction->id)
+        ->call('cancelEditTransaction');
+
+    expect($component->get('editingTransactionId'))->toBeNull();
+    expect($component->get('categoryId'))->toBeNull();
+    expect($component->get('amount'))->toBe('');
+
+    $transaction->refresh();
+    expect((float) $transaction->amount)->toBe(1200.0);
+});
+
+it('does not allow editing a transaction belonging to another household', function (): void {
+    $owner = User::factory()->create();
+    $intruder = User::factory()->create();
+    $category = $owner->currentHousehold->categories()->create(['name' => 'Loyer', 'type' => 'depense', 'position' => 1]);
+    $transaction = $owner->currentHousehold->transactions()->create([
+        'category_id' => $category->id, 'user_id' => $owner->id,
+        'date' => '2026-03-05', 'date_effective' => '2026-03-05', 'amount' => 1200,
+    ]);
+
+    expect(fn () => Livewire::actingAs($intruder)
+        ->test(Index::class)
+        ->call('startEditTransaction', $transaction->id)
+    )->toThrow(ModelNotFoundException::class);
+});
+
 it('lists active recurring transactions due this month as pending', function (): void {
     $this->travelTo(now()->setDate(2026, 3, 10));