This commit standardizes the naming of identifier and API key fields
across the codebase to use consistent camel case (e.g., `ID`, `APIKey`,
`DatabaseURL`). This includes updates to struct fields, method names,
function parameters, and environment variable references. The changes
improve code clarity and maintainability by reducing ambiguity and
aligning with Go naming conventions. No functional behavior is changed.
- Update BookingAgentParser to utilize OpenAI's client for parsing booking data.
- Remove base URL dependency and streamline the initialization process.
- Introduce ResponseData struct to define expected JSON structure from the LLM.
- Add unit tests for BookingAgentParser to validate parsing logic and expected output.
