docs: split model source records and unify project instructions (#113)

* docs: split model sources and consolidate project instructions

* docs: normalize empty model navigation footer

docs/model-sources/templates/SOURCES.md

@@ -0,0 +1,32 @@
+# 供应商：官网证据目录
+
+## 官网证据
+
+### official-models
+
+- 入口：[官方模型文档](https://example.com/docs/models)。
+- 填写地域、适用 API/订阅/套餐、读取结果和核验日期。
+
+## 已知边界与核验说明
+
+写明未获得参数的项目、单位解释、各接入面差异。页面壳不作为已核字段的证明。
+
+<!-- source-metadata:start -->
+```json
+{
+  "formatVersion": 1,
+  "supplier": "替换为已登记的供应商",
+  "checkedAt": "YYYY-MM-DD",
+  "sources": [{
+    "id": "official-models",
+    "url": "https://example.com/docs/models",
+    "kind": "official-doc",
+    "scope": "填写地域和接入面",
+    "retrieval": "unreadable",
+    "checkedAt": "YYYY-MM-DD",
+    "resolvedUrl": null,
+    "contentSha256": null
+  }]
+}
+```
+<!-- source-metadata:end -->