fix: widen actions_taken to list[Any] and improve bot error replies

DispatchResponse declared actions_taken as list[dict] but agents return
list[str], causing a 422 on every successful upload.

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

agent_service/routers/dispatch.py

@@ -5,7 +5,7 @@ import hmac
 import logging
 import time
 import uuid
-from typing import Optional
+from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Request, status
 from pydantic import BaseModel, Field
@@ -31,7 +31,7 @@ class DispatchResponse(BaseModel):
     reply: str
     agent_reports: list[dict] = []
     escalations: list[str] = []
-    actions_taken: list[dict] = []
+    actions_taken: list[Any] = []
     session_id: Optional[str] = None