fix(api): require write permission for validation endpoints

Validation operations should require write permissions as they trigger
state-changing actions. Updated middleware for:
- POST /api/v1/cloud-tokens/{uuid}/validate
- GET /api/v1/servers/{uuid}/validate

Added tests to verify read-only tokens cannot access these endpoints.

tests/Feature/ApiTokenPermissionTest.php

@@ -73,3 +73,28 @@ describe('POST /api/v1/servers', function () {
         $response->assertStatus(403);
     });
 });
+
+describe('GET /api/v1/servers/{uuid}/validate', function () {
+    test('read-only token cannot trigger server validation', function () {
+        $token = $this->user->createToken('read-only', ['read']);
+
+        $response = $this->withHeaders([
+            'Authorization' => 'Bearer '.$token->plainTextToken,
+        ])->getJson('/api/v1/servers/fake-uuid/validate');
+
+        $response->assertStatus(403);
+    });
+});
+
+describe('POST /api/v1/cloud-tokens/{uuid}/validate', function () {
+    test('read-only token cannot validate cloud provider token', function () {
+        $token = $this->user->createToken('read-only', ['read']);
+
+        $response = $this->withHeaders([
+            'Authorization' => 'Bearer '.$token->plainTextToken,
+            'Content-Type' => 'application/json',
+        ])->postJson('/api/v1/cloud-tokens/fake-uuid/validate');
+
+        $response->assertStatus(403);
+    });
+});