fix: normalize DeepSeek non-standard tool_calls format

Systematic debugging revealed DeepSeek returns tool_calls in non-standard
format that bypasses LangChain's parse_tool_call():

**Root Cause:**
- OpenAI standard: {function: {name, arguments}, id}
- DeepSeek format: {name, args, id}
- LangChain's parse_tool_call() returns None when no 'function' key
- Result: Raw tool_call with string args → Pydantic validation error

**Solution:**
- ToolCallArgsParsingWrapper detects non-standard format
- Normalizes to OpenAI standard before LangChain processing
- Converts {name, args, id} → {function: {name, arguments}, id}
- Added diagnostic logging to identify format variations

**Impact:**
- DeepSeek models now work via OpenRouter
- No breaking changes to other providers (defensive design)
- Diagnostic logs help debug future format issues

Fixes validation errors:
  tool_calls.0.args: Input should be a valid dictionary
  [type=dict_type, input_value='{"symbol": "GILD", ...}', input_type=str]

agent/base_agent/base_agent.py

@@ -33,6 +33,7 @@ from tools.deployment_config import (
 from agent.context_injector import ContextInjector
 from agent.pnl_calculator import DailyPnLCalculator
 from agent.reasoning_summarizer import ReasoningSummarizer
+from agent.chat_model_wrapper import ToolCallArgsParsingWrapper
 
 # Load environment variables
 load_dotenv()
@@ -211,14 +212,16 @@ class BaseAgent:
                 self.model = MockChatModel(date="2025-01-01")  # Date will be updated per session
                 print(f"🤖 Using MockChatModel (DEV mode)")
             else:
-                self.model = ChatOpenAI(
+                base_model = ChatOpenAI(
                     model=self.basemodel,
                     base_url=self.openai_base_url,
                     api_key=self.openai_api_key,
                     max_retries=3,
                     timeout=30
                 )
-                print(f"🤖 Using {self.basemodel} (PROD mode)")
+                # Wrap model with diagnostic wrapper
+                self.model = ToolCallArgsParsingWrapper(model=base_model)
+                print(f"🤖 Using {self.basemodel} (PROD mode) with diagnostic wrapper")
         except Exception as e:
             raise RuntimeError(f"❌ Failed to initialize AI model: {e}")