feat(agent): Add endpoint to fetch agent system prompt configuration by workflow ID

Summary

This MR introduces a new API endpoint to retrieve the system prompt configuration for a CustomerCare agent using its N8N workflow ID.

Changes

• Controller: Added AgentSystemPromptConfigController exposing GET /api/customer-care/agents/agent-system-prompt-config/{workflowId}
• Service: Implemented AgentSystemPromptConfigServiceImpl to fetch active agent by workflow ID
• Mapper: Created AgentSystemPromptConfigMapper to convert entity to response DTO
• DTOs: Added response models:
  • AgentSystemPromptConfigResponse (main response)
  • CustomInstructionResponse
  • StandardInstructionCategoryResponse
  • WorkingHoursResponse

Response includes

• Tone & voice settings
• Response style
• Language configuration (auto-detection, default language)
• Blocked keywords
• Standard & custom instructions (suggestions/restrictions) with active = true
• Working hours schedule data
• Enabled objective types with active = true