Add super-admin Administration section and restructure global vs company settings

- Add Administration sidebar section (super-admin only) with Companies, Users, and Global Settings pages
- Add super-admin middleware, controllers, and API routes under /api/v1/super-admin/
- Allow super-admins to manage all companies and users across tenants
- Add user impersonation with short-lived tokens, audit logging, and UI banner
- Move system-level settings (Mail, PDF, Backup, Update, File Disk) from per-company to Administration > Global Settings
- Convert save_pdf_to_disk from CompanySetting to global Setting
- Add per-company mail configuration overrides (optional, falls back to global)
- Add CompanyMailConfigService to apply company mail config before sending emails

app/Http/Resources/CompanyResource.php

@@ -24,9 +24,14 @@ class CompanyResource extends JsonResource
             'unique_hash' => $this->unique_hash,
             'owner_id' => $this->owner_id,
             'slug' => $this->slug,
+            'created_at' => $this->created_at,
+            'updated_at' => $this->updated_at,
             'address' => $this->when($this->address()->exists(), function () {
                 return new AddressResource($this->address);
             }),
+            'owner' => $this->when($this->relationLoaded('owner'), function () {
+                return new UserResource($this->owner);
+            }),
             'roles' => RoleResource::collection($this->roles),
         ];
     }