fix(graph): resolve instrument identity to stop wrong-company hallucination

Agents had no ground-truth ticker→company mapping, so the market analyst
could pattern-match a price chart to the wrong company (e.g. TOTDY read as
"TotalEnergies"), and every downstream agent inherited the bad framing.

Resolve identity once at run start via a cached, fail-open yfinance lookup
and inject company/sector/exchange into the shared instrument context that
all twelve agents consume, with an explicit do-not-substitute instruction.
Resolution runs on both the propagate() and CLI entry points.

Also replaces the bare "Continue" message-clear placeholder, which some
OpenAI-compatible providers interpreted as the user task, with a
context-anchored placeholder carrying the resolved identity and date.

#814 #888

tradingagents/agents/trader/trader.py

@@ -8,7 +8,7 @@ from langchain_core.messages import AIMessage
 
 from tradingagents.agents.schemas import TraderProposal, render_trader_proposal
 from tradingagents.agents.utils.agent_utils import (
-    build_instrument_context,
+    get_instrument_context_from_state,
     get_language_instruction,
 )
 from tradingagents.agents.utils.structured import (
@@ -22,8 +22,7 @@ def create_trader(llm):
 
     def trader_node(state, name):
         company_name = state["company_of_interest"]
-        asset_type = state.get("asset_type", "stock")
-        instrument_context = build_instrument_context(company_name, asset_type)
+        instrument_context = get_instrument_context_from_state(state)
         investment_plan = state["investment_plan"]
 
         messages = [