feat: add bulk client notifications and email enhancements with review fixes (Stories 3.4 & 3.5)

Story 3-4: Bulk client notification scheduling — BulkNotificationController,
BulkActionBar component, checkbox selection on declarations index.

Story 3-5: Email notification enhancement — observer-driven email on
en_attente_client, cache invalidation on ferme, workspace branding on
all email templates, 11 feature tests.

Code review fixes:
- Move bulk-notify route above resource wildcard to prevent shadowing
- Add static $suppressEmail flag to prevent observer double-sending
  when DeclarationMessageController already sends the email
- Fix canBulkNotify logic (was granting workers access)
- Add WorkspaceUserRole check to BulkNotifyRequest::authorize()
- Replace firstOrCreate with explicit invitation lookup that syncs
  client email and handles used/expired invitations correctly
- Watch declarations.data instead of current_page to clear selection
  on filter/sort changes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/Http/Controllers/BulkNotificationController.php

@@ -0,0 +1,106 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Concerns\HasWorkspaceScope;
+use App\Enums\DeclarationStatus;
+use App\Http\Requests\BulkNotifyRequest;
+use App\Mail\DeclarationFileRequestMail;
+use App\Models\Declaration;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Mail;
+
+class BulkNotificationController extends Controller
+{
+    use HasWorkspaceScope;
+
+    public function store(BulkNotifyRequest $request): RedirectResponse
+    {
+        $workspace = $this->currentWorkspace();
+        $user = $request->user();
+        $workspaceUser = $user->currentWorkspaceUser();
+
+        $declarations = Declaration::where('workspace_id', $workspace->id)
+            ->forUser($user, $workspaceUser)
+            ->where('status', DeclarationStatus::EnAttenteClient)
+            ->whereIn('id', $request->validated('declaration_ids'))
+            ->with('client')
+            ->get()
+            ->filter(fn (Declaration $d) => $d->client !== null);
+
+        if ($declarations->isEmpty()) {
+            return back()->with('flash', [
+                'type' => 'warning',
+                'message' => 'Aucune déclaration éligible trouvée.',
+            ]);
+        }
+
+        // DB transaction for invitation creation/update, collect mail data for queuing after commit
+        $mailJobs = DB::transaction(function () use ($declarations) {
+            $jobs = [];
+
+            foreach ($declarations as $declaration) {
+                $clientEmail = $declaration->client->contact_email;
+
+                $invitation = $declaration->invitations()
+                    ->whereNull('used_at')
+                    ->latest()
+                    ->first();
+
+                if ($invitation && $invitation->isValid()) {
+                    if ($invitation->email !== $clientEmail) {
+                        $invitation->update(['email' => $clientEmail]);
+                        $invitation->refresh();
+                    }
+                } elseif ($invitation && ! $invitation->isValid()) {
+                    $invitation->update([
+                        'email' => $clientEmail,
+                        'expires_at' => now()->addDays(30),
+                    ]);
+                    $invitation->refresh();
+                } else {
+                    $invitation = $declaration->invitations()->create([
+                        'email' => $clientEmail,
+                        'expires_at' => now()->addDays(30),
+                    ]);
+                }
+
+                $body = 'Nous vous invitons à déposer les documents complémentaires pour votre déclaration "'
+                    . $declaration->title . '".';
+
+                $jobs[] = [
+                    'email' => $declaration->client->contact_email,
+                    'mailable' => new DeclarationFileRequestMail($declaration, $invitation, $body),
+                ];
+            }
+
+            return $jobs;
+        });
+
+        // Queue emails outside transaction (Redis is not transactional with MySQL)
+        foreach ($mailJobs as $job) {
+            Mail::to($job['email'])->queue($job['mailable']);
+        }
+
+        activity()
+            ->performedOn($workspace)
+            ->causedBy($user)
+            ->withProperties([
+                'count' => $declarations->count(),
+                'declaration_ids' => $declarations->pluck('id')->all(),
+            ])
+            ->log('bulk_client_notification');
+
+        // Invalidate notification caches for workspace users
+        $workspace->users->each(function ($wsUser) use ($workspace) {
+            Cache::forget("user:{$wsUser->id}:workspace:{$workspace->id}:unread_notifications");
+        });
+
+        return back()->with('flash', [
+            'type' => 'success',
+            'message' => $declarations->count() . ' notifications envoyées',
+        ]);
+    }
+}