debug: add comprehensive diagnostic logging for ContextInjector flow

Add instrumentation at component boundaries to trace where ContextInjector values become None:
- ModelDayExecutor: Log ContextInjector creation and set_context() invocation
- BaseAgent.set_context(): Log entry, client creation, tool reload, completion
- Includes object IDs to verify instance identity across boundaries

Part of systematic debugging investigation for issue #TBD.

agent/base_agent/base_agent.py

@@ -232,17 +232,24 @@ class BaseAgent:
             context_injector: Configured ContextInjector instance with
                             correct signature, today_date, job_id, session_id
         """
+        print(f"[DEBUG] set_context() ENTRY: Received context_injector with signature={context_injector.signature}, date={context_injector.today_date}, job_id={context_injector.job_id}, session_id={context_injector.session_id}")
+
         self.context_injector = context_injector
+        print(f"[DEBUG] set_context(): Set self.context_injector, id={id(self.context_injector)}")
 
         # Recreate MCP client with the interceptor
         # Note: We need to recreate because MultiServerMCPClient doesn't have add_interceptor()
+        print(f"[DEBUG] set_context(): Creating new MCP client with interceptor, id={id(context_injector)}")
         self.client = MultiServerMCPClient(
             self.mcp_config,
             tool_interceptors=[context_injector]
         )
+        print(f"[DEBUG] set_context(): MCP client created")
 
         # CRITICAL: Reload tools from new client so they use the interceptor
+        print(f"[DEBUG] set_context(): Reloading tools...")
         self.tools = await self.client.get_tools()
+        print(f"[DEBUG] set_context(): Tools reloaded, count={len(self.tools)}")
 
         print(f"✅ Context injected: signature={context_injector.signature}, "
               f"date={context_injector.today_date}, job_id={context_injector.job_id}, "

api/model_day_executor.py

@@ -140,7 +140,10 @@ class ModelDayExecutor:
                 job_id=self.job_id,
                 session_id=session_id
             )
+            logger.info(f"[DEBUG] ModelDayExecutor: Created ContextInjector with signature={self.model_sig}, date={self.date}, job_id={self.job_id}, session_id={session_id}")
+            logger.info(f"[DEBUG] ModelDayExecutor: Calling await agent.set_context()")
             await agent.set_context(context_injector)
+            logger.info(f"[DEBUG] ModelDayExecutor: set_context() completed")
 
             # Run trading session
             logger.info(f"Running trading session for {self.model_sig} on {self.date}")