chore(schemas): runtime-recommended 收紧 sha256 为必填（6 平台齐全） (#46)

与主仓库 lib/schemas/agent-service/runtime-manifest.ts 同源导出，强化归档防篡改校验

schemas/runtime-recommended.schema.json

@@ -15,7 +15,8 @@
         "name",
         "version",
         "distTag",
-        "archives"
+        "archives",
+        "sha256"
       ],
       "properties": {
         "name": {
@@ -72,6 +73,14 @@
         "sha256": {
           "type": "object",
           "description": "各平台归档的 SHA-256 校验值（十六进制小写）。构建脚本下载后校验，防止归档被镜像/代理篡改或截断",
+          "required": [
+            "darwin-arm64",
+            "darwin-x64",
+            "win32-x64",
+            "win32-arm64",
+            "linux-x64",
+            "linux-arm64"
+          ],
           "properties": {
             "darwin-arm64": {
               "type": "string",
@@ -114,7 +123,8 @@
       "description": "Node.js 推荐版本（官方 dist 归档，经内置 Volta 安装）",
       "required": [
         "version",
-        "archives"
+        "archives",
+        "sha256"
       ],
       "properties": {
         "version": {
@@ -167,6 +177,14 @@
         "sha256": {
           "type": "object",
           "description": "各平台归档的 SHA-256 校验值（十六进制小写）。构建脚本下载后校验，防止归档被镜像/代理篡改或截断",
+          "required": [
+            "darwin-arm64",
+            "darwin-x64",
+            "win32-x64",
+            "win32-arm64",
+            "linux-x64",
+            "linux-arm64"
+          ],
           "properties": {
             "darwin-arm64": {
               "type": "string",