feat: complete Epic 0 — foundation migration & infrastructure setup

Stories 0.2-0.5: rename folders→declarations (backend+frontend), configure
Redis for cache/queue/sessions, add foundation database migrations
(permissions, archived_at), replace DeclarationStatus enum with architecture
lifecycle values, create DeclarationObserver for status transition validation
and auto-archive, fix controller status transitions to respect observer rules.

93 tests pass (240 assertions).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Providers/AppServiceProvider.php

@@ -2,6 +2,8 @@
 
 namespace App\Providers;
 
+use App\Models\Declaration;
+use App\Observers\DeclarationObserver;
 use Carbon\CarbonImmutable;
 use Illuminate\Support\Facades\Date;
 use Illuminate\Support\Facades\DB;
@@ -24,6 +26,8 @@ class AppServiceProvider extends ServiceProvider
     public function boot(): void
     {
         $this->configureDefaults();
+
+        Declaration::observe(DeclarationObserver::class);
     }
 
     /**