Add Kaigen API health check and configuration

- Introduced Kaigen configuration section in appsettings.Oda.json with BaseUrl.
- Added HTTP client for Kaigen API health check in Program.cs.
- Registered KaigenHealthCheck service for monitoring Kaigen API connectivity.

src/Managing.Api/appsettings.Oda.json

@@ -12,6 +12,9 @@
     "AppId": "cm6f47n1l003jx7mjwaembhup",
     "AppSecret": "63Chz2z5M8TgR5qc8dznSLRAGTHTyPU4cjdQobrBF1Cx5tszZpTuFgyrRd7hZ2k6HpwDz3GEwQZzsCqHb8Z311bF"
   },
+  "Kaigen": {
+    "BaseUrl": "https://kaigen-back.apps.managing.live"
+  },
   "Serilog": {
     "MinimumLevel": {
       "Default": "Information",