Revert "update metric using timer"

This reverts commit 60f36d3.

Author: lizk886

src/main/java/com/uid2/operator/Main.java

@@ -69,7 +69,9 @@
 public class Main {
     private static final Logger LOGGER = LoggerFactory.getLogger(Main.class);
 
+    // Startup timing field
     private static volatile Instant startupBeginTime;
+
     private final JsonObject config;
     private final Vertx vertx;
     private final ApplicationVersion appVersion;
@@ -246,11 +248,25 @@ private KeyManager getKeyManager() {
         return new KeyManager(this.keysetKeyStore, this.keysetProvider);
     }
 
+    /**
+     * Calculate startup duration following established codebase patterns.
+     * @return Duration from startup begin to completion, or null if timing data is invalid
+     */
+    private static Duration getStartupDuration() {
+        if (startupBeginTime == null) {
+            return null;
+        }
+        return Duration.between(startupBeginTime, Instant.now());
+    }
+
     public static void recordStartupComplete() {
-        if (startupBeginTime == null) return;
-        final Duration d = Duration.between(startupBeginTime, Instant.now());
-        Timer.builder("uid2_operator_startup_duration").register(globalRegistry).record(d);
-        LOGGER.info("Startup in {} ms", d.toMillis());
+        final Duration d = getStartupDuration();
+        if (d == null) return;
+        Timer
+            .builder("uid2_operator_startup_duration")
+            .register(globalRegistry)
+            .record(d);
+        LOGGER.info("Operator startup completed in {} seconds", String.format("%.3f", d.toMillis() / 1000.0));
     }
 
     public static void main(String[] args) throws Exception {