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>

database/factories/DeclarationFactory.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Database\Factories;
+
+use App\Enums\DeclarationPriority;
+use App\Enums\DeclarationStatus;
+use App\Enums\DeclarationType;
+use App\Models\Client;
+use App\Models\Workspace;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends \Illuminate\Database\Eloquent\Factories\Factory<\App\Models\Declaration>
+ */
+class DeclarationFactory extends Factory
+{
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        $workspace = Workspace::factory()->create();
+        $client = Client::factory()->create(['workspace_id' => $workspace->id]);
+
+        $year = fake()->numberBetween(2024, 2026);
+        $excludeOldVat = array_filter(DeclarationType::getValues(), fn ($v) => $v !== 'vat');
+        $type = fake()->randomElement(array_values($excludeOldVat));
+
+        $isVatMonthly = $type === 'vat_monthly';
+        $isVatQuarterly = $type === 'vat_quarterly';
+
+        return [
+            'workspace_id' => $workspace->id,
+            'client_id' => $client->id,
+            'created_by' => null,
+            'title' => 'Déclaration '.$this->typeLabel($type).' - '.$year,
+            'type' => $type,
+            'period_year' => $year,
+            'period_month' => $isVatMonthly ? fake()->numberBetween(1, 12) : null,
+            'period_quarter' => $isVatQuarterly ? fake()->numberBetween(1, 4) : null,
+            'due_date' => fake()->dateTimeBetween('now', '+3 months'),
+            'status' => DeclarationStatus::Created,
+            'priority' => fake()->randomElement(DeclarationPriority::getValues()),
+            'assigned_to' => null,
+            'validated_at' => null,
+            'closed_at' => null,
+            'notes_internal' => fake()->optional(0.3)->sentence(),
+            'notes_client' => null,
+        ];
+    }
+
+    /**
+     * Configure the model factory to use existing workspace and client.
+     */
+    public function forWorkspace(Workspace $workspace): static
+    {
+        return $this->state(fn () => [
+            'workspace_id' => $workspace->id,
+            'client_id' => Client::factory()->create(['workspace_id' => $workspace->id])->id,
+        ]);
+    }
+
+    private function typeLabel(string $type): string
+    {
+        return match ($type) {
+            'vat' => 'TVA',
+            'vat_monthly' => 'TVA mensuelle',
+            'vat_quarterly' => 'TVA trimestrielle',
+            'corporate_tax' => 'IS',
+            'income_tax' => 'IR',
+            'cnss' => 'CNSS',
+            'annual_balance' => 'Bilan',
+            default => 'Autre',
+        };
+    }
+}