domain_study addition and enhancement

[CaesarGhazi]

This marks the initial domain study for Milestone 1. The following documents have been created and added to the _domain_study folder:

• problem_statement.md: Describes the challenge of student engagement in online learning based on observations and experiences.

• background_review: Includes our research in a selected topic related to our chosen domain.

• systems_thinking_analysis.md: Applies systems thinking to identify the structures and mental models contributing to disengagement.

• research_question.md: Proposes an actionable, specific, and measurable research question aligned with the project scope(To be further discussed later).

• README.md: Summarizes the contents of this domain study folder for easier navigation.