chore(config): remove the no-op analyst_concurrency_limit knob

The knob was accepted but inert — analysts run strictly sequentially and the
value was never used. Remove it rather than ship a misleading config key.
Parallel analyst execution is tracked for v0.3 (#634/#671/#487).

tradingagents/graph/setup.py

@@ -35,14 +35,12 @@ class GraphSetup:
         deep_thinking_llm: Any,
         tool_nodes: dict[str, ToolNode],
         conditional_logic: ConditionalLogic,
-        analyst_concurrency_limit: int = 1,
     ):
         """Initialize with required components."""
         self.quick_thinking_llm = quick_thinking_llm
         self.deep_thinking_llm = deep_thinking_llm
         self.tool_nodes = tool_nodes
         self.conditional_logic = conditional_logic
-        self.analyst_concurrency_limit = analyst_concurrency_limit
 
     def setup_graph(
         self, selected_analysts=("market", "social", "news", "fundamentals")
@@ -56,10 +54,7 @@ class GraphSetup:
                 - "news": News analyst
                 - "fundamentals": Fundamentals analyst
         """
-        plan = build_analyst_execution_plan(
-            selected_analysts,
-            concurrency_limit=self.analyst_concurrency_limit,
-        )
+        plan = build_analyst_execution_plan(selected_analysts)
 
         analyst_factories = {
             "market": lambda: create_market_analyst(self.quick_thinking_llm),