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/test_thinkdeep_validation.py

@@ -415,7 +415,7 @@ class ThinkDeepWorkflowValidationTest(ConversationBaseTest):
                         expert_analysis = {"analysis": expert_analysis}
 
             # Check for expected analysis content (checking common patterns)
-            analysis_text = json.dumps(expert_analysis).lower()
+            analysis_text = json.dumps(expert_analysis, ensure_ascii=False).lower()
 
             # Look for thinking analysis validation
             thinking_indicators = ["migration", "strategy", "microservices", "risk", "approach", "implementation"]