Merge PR #309: fix(timezone): timezone-aware now() for prompt, cron, and execute_code

Authored by areu01or00. Adds timezone support via hermes_time.now() helper
with IANA timezone resolution (HERMES_TIMEZONE env → config.yaml → server-local).
Updates system prompt timestamp, cron scheduling, and execute_code sandbox TZ
injection. Includes config migration (v4→v5) and comprehensive test coverage.

gateway/run.py

@@ -93,6 +93,11 @@ if _config_path.exists():
         if _agent_cfg and isinstance(_agent_cfg, dict):
             if "max_turns" in _agent_cfg:
                 os.environ["HERMES_MAX_ITERATIONS"] = str(_agent_cfg["max_turns"])
+        # Timezone: bridge config.yaml → HERMES_TIMEZONE env var.
+        # HERMES_TIMEZONE from .env takes precedence (already in os.environ).
+        _tz_cfg = _cfg.get("timezone", "")
+        if _tz_cfg and isinstance(_tz_cfg, str) and "HERMES_TIMEZONE" not in os.environ:
+            os.environ["HERMES_TIMEZONE"] = _tz_cfg.strip()
     except Exception:
         pass  # Non-fatal; gateway can still run with .env values