refactor(agents): organise the agents package by what each module holds

- tools.py: the analysts' data tools, previously seven modules under utils
- context.py (was agent_utils, without its tool re-exports), state.py, rating.py and structured.py sit beside schemas.py
- every role package has an __init__

tests/test_rating_integrity.py

@@ -11,7 +11,7 @@ from __future__ import annotations
 
 import pytest
 
-from tradingagents.agents.utils.rating import RATING_REVIEW, extract_rating, parse_rating
+from tradingagents.agents.rating import RATING_REVIEW, extract_rating, parse_rating
 
 INVERTED = ("The aggressive analyst pushed hard for a Buy on the AI backlog, but the "
             "conservative case on margin compression carried the debate. "
@@ -74,8 +74,8 @@ def test_the_memory_log_records_review_rather_than_a_tradeable_hold(tmp_path):
 
 @pytest.mark.unit
 def test_the_signal_and_the_log_agree_on_the_same_decision(tmp_path):
+    from tradingagents.agents.rating import parse_rating
     from tradingagents.agents.utils.memory import TradingMemoryLog
-    from tradingagents.agents.utils.rating import parse_rating
 
     log = TradingMemoryLog({"memory_log_path": str(tmp_path / "m.md")})
     for text in (INVERTED, REFUSAL, "**Rating**: Buy\n\nAccumulate."):
@@ -121,7 +121,7 @@ def test_the_cli_says_when_a_run_produced_no_usable_rating(monkeypatch, tmp_path
             pass
 
         def process_signal(self, text):
-            from tradingagents.agents.utils.rating import parse_rating
+            from tradingagents.agents.rating import parse_rating
             return parse_rating(text)
 
         def get_graph_args(self, callbacks=None):