CME-541: Add health endpoint sampling to Application Insights config

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: chrisworthcgi

lib/applicationinsights.json

@@ -2,5 +2,22 @@
   "connectionString": "${file:/mnt/secrets/rd/app-insights-connection-string}",
   "role": {
     "name": "location reference data load"
+  },
+  "preview": {
+    "sampling": {
+      "overrides": [
+        {
+          "telemetryType": "request",
+          "attributes": [
+            {
+              "key": "http.url",
+              "value": "https?://[^/]+/health.*",
+              "matchType": "regexp"
+            }
+          ],
+          "percentage": 1
+        }
+      ]
+    }
   }
 }