feat: migrate trade tools to write to actions table (new schema)

This commit implements Task 1 from the schema migration plan:
- Trade tools (buy/sell) now write to actions table instead of old positions table
- Added trading_day_id parameter to buy/sell functions
- Updated ContextInjector to inject trading_day_id
- Updated RuntimeConfigManager to include TRADING_DAY_ID in config
- Removed P&L calculation from trade functions (now done at trading_days level)
- Added tests verifying correct behavior with new schema

Changes:
- agent_tools/tool_trade.py: Modified _buy_impl and _sell_impl to write to actions table
- agent/context_injector.py: Added trading_day_id parameter and injection logic
- api/model_day_executor.py: Updated to read trading_day_id from runtime config
- api/runtime_manager.py: Added trading_day_id to config initialization
- tests/unit/test_trade_tools_new_schema.py: New tests for new schema compliance

All tests passing.

agent/context_injector.py

@@ -17,7 +17,8 @@ class ContextInjector:
         client = MultiServerMCPClient(config, tool_interceptors=[interceptor])
     """
 
-    def __init__(self, signature: str, today_date: str, job_id: str = None, session_id: int = None):
+    def __init__(self, signature: str, today_date: str, job_id: str = None,
+                 session_id: int = None, trading_day_id: int = None):
         """
         Initialize context injector.
 
@@ -25,12 +26,14 @@ class ContextInjector:
             signature: Model signature to inject
             today_date: Trading date to inject
             job_id: Job UUID to inject (optional)
-            session_id: Trading session ID to inject (optional, updated during execution)
+            session_id: Trading session ID to inject (optional, DEPRECATED)
+            trading_day_id: Trading day ID to inject (optional)
         """
         self.signature = signature
         self.today_date = today_date
         self.job_id = job_id
-        self.session_id = session_id
+        self.session_id = session_id  # Deprecated but kept for compatibility
+        self.trading_day_id = trading_day_id
 
     async def __call__(
         self,
@@ -50,7 +53,7 @@ class ContextInjector:
         # Inject context parameters for trade tools
         if request.name in ["buy", "sell"]:
             # Debug: Log self attributes BEFORE injection
-            print(f"[ContextInjector.__call__] ENTRY: id={id(self)}, self.signature={self.signature}, self.today_date={self.today_date}, self.job_id={self.job_id}, self.session_id={self.session_id}")
+            print(f"[ContextInjector.__call__] ENTRY: id={id(self)}, self.signature={self.signature}, self.today_date={self.today_date}, self.job_id={self.job_id}, self.session_id={self.session_id}, self.trading_day_id={self.trading_day_id}")
             print(f"[ContextInjector.__call__] Args BEFORE injection: {request.args}")
 
             # ALWAYS inject/override context parameters (don't trust AI-provided values)
@@ -60,6 +63,8 @@ class ContextInjector:
                 request.args["job_id"] = self.job_id
             if self.session_id:
                 request.args["session_id"] = self.session_id
+            if self.trading_day_id:
+                request.args["trading_day_id"] = self.trading_day_id
 
             # Debug logging
             print(f"[ContextInjector] Tool: {request.name}, Args after injection: {request.args}")