feat: two-role system — super_admin & admin program (Fasa 12)

- Replace is_admin boolean with role enum('super_admin','admin') via migration
- ProgramPolicy: admin program can only view/edit/delete own programs
- EnsureIsAdmin: accepts both roles; EnsureSuperAdmin: super_admin only
- UserController + views: super_admin can manage admin accounts
- Sidebar: user management link & role badge gated on isSuperAdmin()
- Fix Controller base class: add AuthorizesRequests trait
- Fix tests: replace nonAdmin() (invalid enum) with adminProgram() against super_admin-only route

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

app/Policies/ProgramPolicy.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace App\Policies;
+
+use App\Models\Program;
+use App\Models\User;
+
+class ProgramPolicy
+{
+    public function viewAny(User $user): bool
+    {
+        return true; // Both roles can see programs list (scoped per controller)
+    }
+
+    public function view(User $user, Program $program): bool
+    {
+        return $user->canAccessProgram($program);
+    }
+
+    public function create(User $user): bool
+    {
+        return true; // Both roles can create programs
+    }
+
+    public function update(User $user, Program $program): bool
+    {
+        return $user->canAccessProgram($program);
+    }
+
+    public function delete(User $user, Program $program): bool
+    {
+        return $user->canAccessProgram($program);
+    }
+}