feat(refactor-module-logic): Create spec for refactoring application modules (003)

feat(refactor-module-logic): Create spec for refactoring application modules (003) This commit introduces the specification for refactoring the application's module structure, marked as feature 003. It outlines the movement of the statistics calculator from the 'obsidian' module to 'logseq_converter', and parsing logic from 'obsidian' to 'logseq'. The goal is to improve code organization, maintainability, and extensibility by ensuring each module has a clear, focused responsibility. The specification includes user scenarios (developer-centric), functional requirements, and measurable success criteria to guide the implementation and verification of the refactoring.