fix(heartbeat): inject shared current time context into phase 1

nanobot/heartbeat/service.py

@@ -3,7 +3,6 @@
 from __future__ import annotations
 
 import asyncio
-from datetime import datetime, timezone
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Callable, Coroutine
 
@@ -88,19 +87,13 @@ class HeartbeatService:
 
         Returns (action, tasks) where action is 'skip' or 'run'.
         """
-        now_str = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
+        from nanobot.utils.helpers import current_time_str
 
         response = await self.provider.chat_with_retry(
             messages=[
-                {"role": "system", "content": (
-                    "You are a heartbeat agent. Call the heartbeat tool to report your decision. "
-                    "The current date/time is provided so you can evaluate time-based conditions. "
-                    "Choose 'run' if there are active tasks to execute. "
-                    "Choose 'skip' if the file has no actionable tasks, if blocking conditions "
-                    "are not yet met, or if tasks are scheduled for a future time that has not arrived yet."
-                )},
+                {"role": "system", "content": "You are a heartbeat agent. Call the heartbeat tool to report your decision."},
                 {"role": "user", "content": (
-                    f"Current date/time: {now_str}\n\n"
+                    f"Current Time: {current_time_str()}\n\n"
                     "Review the following HEARTBEAT.md and decide whether there are active tasks.\n\n"
                     f"{content}"
                 )},