feat: Add LOCAL variable support for responses with UTF-8 JSON encoding.

Description: This feature adds support for UTF-8 encoding in JSON responses, allowing for proper handling of special characters and emojis.

- Implement unit tests for UTF-8 encoding in various model providers including Gemini, OpenAI, and OpenAI Compatible.
- Validate UTF-8 support in token counting, content generation, and error handling.
- Introduce tests for JSON serialization ensuring proper handling of French characters and emojis.
- Create tests for language instruction generation based on locale settings.
- Validate UTF-8 handling in workflow tools including AnalyzeTool, CodereviewTool, and DebugIssueTool.
- Ensure that all tests check for correct UTF-8 character preservation and proper JSON formatting.
- Add integration tests to verify the interaction between locale settings and model responses.

simulator_tests/base_test.py

@@ -136,10 +136,12 @@ class Calculator:
                 "id": 2,
                 "method": "tools/call",
                 "params": {"name": tool_name, "arguments": params},
-            }
-
-            # Combine all messages
-            messages = [json.dumps(init_request), json.dumps(initialized_notification), json.dumps(tool_request)]
+            }            # Combine all messages
+            messages = [
+                json.dumps(init_request, ensure_ascii=False), 
+                json.dumps(initialized_notification, ensure_ascii=False), 
+                json.dumps(tool_request, ensure_ascii=False)
+            ]
 
             # Join with newlines as MCP expects
             input_data = "\n".join(messages) + "\n"