Fix: migrate all remaining main_agent imports to current_app

email, scheduled_messages scheduler, and cron blueprints still imported
main_agent directly from agents. All now use current_app.main_agent so
they read the initialized value set by build_agent() in the lifespan.

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

blueprints/cron/__init__.py

@@ -3,7 +3,7 @@ import logging
 import os
 from datetime import datetime, timezone
 
-from quart import Blueprint, jsonify, request
+from quart import Blueprint, current_app, jsonify, request
 
 from blueprints.users.decorators import admin_required
 from blueprints.scheduled_messages.models import MessageChannel
@@ -137,14 +137,9 @@ async def trigger_job(job_id: str):
         return jsonify({"skipped": True}), 200
 
     try:
-        from blueprints.conversation.agents import main_agent
-        from blueprints.conversation.prompts import SIMBA_SYSTEM_PROMPT
-
-        messages_payload = [
-            {"role": "system", "content": SIMBA_SYSTEM_PROMPT},
-            {"role": "user", "content": job.prompt},
-        ]
-        response = await main_agent.ainvoke({"messages": messages_payload})
+        response = await current_app.main_agent.ainvoke(
+            {"messages": [{"role": "user", "content": job.prompt}]}
+        )
         result = response.get("messages", [])[-1].content
 
         if job.channel == MessageChannel.IMESSAGE: