fix(data): complete verified contracts and source maintenance (#114)

docs/model-sources/providers/xai/SOURCES.md

@@ -11,6 +11,11 @@
 - 入口：[xai](https://docs.x.ai/developers/release-notes)
 - 类型：`official-doc`；当前读取状态：`fetched`；地域/接入面：`xai 官方入口；具体地域与接入面待该页面逐字段确认`。
 
+### grok43-model
+
+- 入口：[grok43-model](https://docs.x.ai/developers/models/grok-4.3)
+- 类型：`official-doc`；读取状态：`fetched`；适用范围：xAI Grok4.3 直连 API；USD 标准价格。
+
 ## 已知边界与核验说明
 
 已登记官方入口并尝试读取。表中仅标为已核字段的部分有此次核对记录；其余存量参数待逐字段复核。
@@ -33,8 +38,22 @@
       "checkedAt": "2026-10-03",
       "contentSha256": "15620ca6445ab3d08a0bfb7e42ea5ade12bac808ef11df763a99cd865ae6c7ae",
       "resolvedUrl": "https://docs.x.ai/developers/release-notes"
+    },
+    {
+      "id": "grok43-model",
+      "url": "https://docs.x.ai/developers/models/grok-4.3",
+      "kind": "official-doc",
+      "scope": "xAI Grok4.3 直连 API；USD 标准价格",
+      "retrieval": "fetched",
+      "checkedAt": "2026-10-03",
+      "contentSha256": "bd44aac101032c9eb9cc2896d86c19f2f3233301ac86a32c2efa0249239bbf32",
+      "resolvedUrl": "https://docs.x.ai/developers/models/grok-4.3"
     }
   ]
 }
 ```
 <!-- source-metadata:end -->
+
+## Grok 4.3 档位差异
+
+本轮模型页 Capabilities 明确 none/low/medium/high；Details 表另列 xhigh，存在同页差异。仅采用四个一致档位，默认 low 有明确记录。xhigh 需取得稳定 API 规格或授权请求证据后再开放；未做账号调用验收。