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/Enums/DeclarationPriority.php

@@ -4,7 +4,7 @@ namespace App\Enums;
 
 use BenSampo\Enum\Enum;
 
-final class FolderPriority extends Enum
+final class DeclarationPriority extends Enum
 {
     const Low = 'low';
 

app/Enums/DeclarationStatus.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Enums;
+
+use BenSampo\Enum\Enum;
+
+final class DeclarationStatus extends Enum
+{
+    const Created = 'created';
+
+    const EnCours = 'en_cours';
+
+    const EnAttenteClient = 'en_attente_client';
+
+    const Termine = 'termine';
+
+    const Ferme = 'ferme';
+
+    /**
+     * Get French display labels for each status.
+     *
+     * @return array<string, string>
+     */
+    public static function labels(): array
+    {
+        return [
+            self::Created => 'Créé',
+            self::EnCours => 'En cours',
+            self::EnAttenteClient => 'En attente client',
+            self::Termine => 'Terminé',
+            self::Ferme => 'Fermé',
+        ];
+    }
+
+    /**
+     * Get the valid next statuses for each status per the architecture status flow.
+     *
+     * @return array<string, list<string>>
+     */
+    public static function allowedTransitions(): array
+    {
+        return [
+            self::Created => [self::EnCours],
+            self::EnCours => [self::EnAttenteClient, self::Termine],
+            self::EnAttenteClient => [self::EnCours],
+            self::Termine => [self::Ferme],
+            self::Ferme => [],
+        ];
+    }
+}

app/Enums/DeclarationType.php

@@ -4,7 +4,7 @@ namespace App\Enums;
 
 use BenSampo\Enum\Enum;
 
-final class FolderType extends Enum
+final class DeclarationType extends Enum
 {
     const VAT = 'vat';
 

app/Enums/FolderStatus.php

@@ -1,26 +0,0 @@
-<?php
-
-namespace App\Enums;
-
-use BenSampo\Enum\Enum;
-
-final class FolderStatus extends Enum
-{
-    const Draft = 'draft';
-
-    const WaitingDocuments = 'waiting_documents';
-
-    const DocumentsReceived = 'documents_received';
-
-    const Processing = 'processing';
-
-    const AdditionalDocumentsRequested = 'additional_documents_requested';
-
-    const WaitingClientValidation = 'waiting_client_validation';
-
-    const Validated = 'validated';
-
-    const Closed = 'closed';
-
-    const Cancelled = 'cancelled';
-}