Add partner SMS gateway via Gama SendQuick and document it.

Expose POST /public/sms/send with API key + domain allowlist for external backends like Balout, wire Meshkee OTP/message sends to Gama, and publish Partner SMS docs on /docs/website.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/website-api/Meshkee-Website-API.postman_collection.json

@@ -100,6 +100,10 @@
     {
       "key": "brandId",
       "value": ""
+    },
+    {
+      "key": "smsApiKey",
+      "value": ""
     }
   ],
   "item": [
@@ -1669,6 +1673,34 @@
           }
         }
       ]
+    },
+    {
+      "name": "Partner SMS",
+      "description": "Server-to-server SMS for allowlisted partner domains. Set collection variable `smsApiKey`. Docs: https://api.meshkee.com/docs/website/SMS.md",
+      "item": [
+        {
+          "name": "Send SMS",
+          "request": {
+            "method": "POST",
+            "header": [
+              {
+                "key": "Content-Type",
+                "value": "application/json"
+              },
+              {
+                "key": "X-Api-Key",
+                "value": "{{smsApiKey}}"
+              }
+            ],
+            "body": {
+              "mode": "raw",
+              "raw": "{\n  \"domain\": \"baloutpastry.com\",\n  \"to\": \"09127004945\",\n  \"message\": \"سفارش شما به شماره ی ۱۲۱۱۳۲۲ اماده می باشد.\"\n}"
+            },
+            "url": "{{baseUrl}}/public/sms/send",
+            "description": "Requires allowlisted domain + matching API key. Not for browser JS."
+          }
+        }
+      ]
     }
   ]
 }