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/Models/WorkspaceUser.php

@@ -21,6 +21,7 @@ class WorkspaceUser extends Pivot
      */
     protected $fillable = [
         'role',
+        'permissions',
     ];
 
     /**
@@ -32,6 +33,7 @@ class WorkspaceUser extends Pivot
     {
         return [
             'role' => WorkspaceUserRole::class,
+            'permissions' => 'array',
         ];
     }
 }