feat(admin): exclude health check entries from admin logs

Filter out automated health check log entries (such as `/health`,
`/healthz`, and `/api/v1/health`) from the admin logs view. This
reduces noise in the dashboard caused by frequent container health
pings.

Also added corresponding unit tests to verify the filtering behavior.

backend/libs/handlers/admin.go

@@ -1731,11 +1731,29 @@ func readLogEntries(file string) ([]adminLogEntry, error) {
 		if err := json.Unmarshal(line, &raw); err != nil {
 			continue
 		}
+		if isHealthCheckLogEntry(raw) {
+			continue
+		}
 		entries = append(entries, logEntryFromMap(raw))
 	}
 	return entries, scanner.Err()
 }
 
+func isHealthCheckLogEntry(raw map[string]any) bool {
+	path := strings.TrimSpace(firstLogString(raw, "path", "route"))
+	if path == "" {
+		return false
+	}
+	fields := strings.Fields(path)
+	if len(fields) > 0 {
+		path = fields[len(fields)-1]
+	}
+	if idx := strings.IndexByte(path, '?'); idx >= 0 {
+		path = path[:idx]
+	}
+	return path == "/health" || path == "/healthz" || path == "/api/v1/health"
+}
+
 func logEntryFromMap(raw map[string]any) adminLogEntry {
 	entry := adminLogEntry{
 		Date:     logString(raw, "date"),