fix: show human-readable duration in re-notification messages

Replace raw seconds with d h m s format in "ongoing for ..." strings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hbd/server/threshold.py

@@ -1393,6 +1393,17 @@ class ThresholdChecker:
         else:
             self._check_renotify(host_name, alert_state, metric_path, value, threshold, plugin_data, check_name=check_name, metric_name=metric_name)
 
+    @staticmethod
+    def _human_duration(seconds: float) -> str:
+        s = int(seconds)
+        if s < 120:
+            return f"{s}s"
+        if s < 3600:
+            return f"{s // 60}m {s % 60}s"
+        h, rem = divmod(s, 3600)
+        m = rem // 60
+        return f"{h}h {m}m" if m else f"{h}h"
+
     def _check_renotify(
         self,
         host_name: str,
@@ -1454,9 +1465,9 @@ class ThresholdChecker:
                     check_name=check_name,
                     metric_name=metric_name,
                 )
-                body = f"{value} {threshold_info}, ongoing for {int(now - alert_state.since)}s"
+                body = f"{value} {threshold_info}, ongoing for {self._human_duration(now - alert_state.since)}"
             else:
-                body = f"{value} (ongoing for {int(now - alert_state.since)}s)"
+                body = f"{value} (ongoing for {self._human_duration(now - alert_state.since)})"
             message = f"REMINDER ({alert_state.level.name}): {host_name} - {short_path} = {body}"
 
             from . import hbdclass