feat: 设备卡片显示系统名+版本 + 项目根 version.json

- SystemInfoCollector.platform 新增 release 字段 (内核版本)
- Sentinel 卡片每台设备显示: Linux 6.12.23 | aarch64
- 数据刷新时同步更新系统信息行
- 项目根 version.json: 本地版本清单

当前版本检测:
  UpdateService 每6h从 {repo}/raw/branch/{branch}/version.json 拉取
  对比 base_config.yaml 的 framework.version
  远程 > 本地 → 顶栏绿色按钮 + 设置页更新提示

Co-Authored-By: Claude <noreply@anthropic.com>

plugins/sentinel/__init__.py

@@ -103,6 +103,7 @@ class Plugin(PluginWebMixin):
                 "enabled": n.get("enabled", True),
                 "online": c.get("online", False),
                 "system": c.get("system", {}),
+                "platform": c.get("platform", {}),
                 "last_seen": c.get("last_seen", 0),
                 "error": c.get("error", ""),
             })
@@ -186,6 +187,7 @@ class Plugin(PluginWebMixin):
                 _NODE_CACHE[node.get("id", "")] = {
                     "online": online,
                     "system": sys_info or {},
+                    "platform": (sys_info or {}).get("platform", {}),
                     "last_seen": time.time(),
                     "error": err if not online else "",
                 }
@@ -225,6 +227,7 @@ class Plugin(PluginWebMixin):
                 "enabled": n.get("enabled", True),
                 "online": c.get("online", False),
                 "system": c.get("system", {}),
+                "platform": c.get("platform", {}),
                 "last_seen": c.get("last_seen", 0),
                 "error": c.get("error", ""),
             })