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.

run_agent.py

@@ -1363,7 +1363,8 @@ class AIAgent:
             if context_files_prompt:
                 prompt_parts.append(context_files_prompt)
 
-        now = datetime.now()
+        from hermes_time import now as _hermes_now
+        now = _hermes_now()
         prompt_parts.append(
             f"Conversation started: {now.strftime('%A, %B %d, %Y %I:%M %p')}"
         )