GitBook Documentation Migration

**Description:** The project's feature set (multi-dimensional scoring, constraint programming, UI routing) has outgrown a single-page README. Documentation must be modularized and hosted via GitBook for maintainability and improved UX.

**Technical Tasks:**
- Initialize a new GitBook space linked to this GitHub repository.
- Structure the GitBook into logical sections:
- `Getting Started` (Installation, Quick Start)
- `Data Schema` (Explanation of `Name`, `ScoreN`, `Sep`, `Grp`)
- `Solver Constraints` (Explanation of CP-SAT logic, weighted objectives, and soft penalties)
- `Developer Guide` (Project structure, local environment setup, running tests).
- Configure GitBook/GitHub synchronization (.gitbook.yaml or standard integration) to ensure docs are version-controlled alongside the codebase.
- Replace the extensive technical explanations in the root `README.md` with a high-level summary and a prominent link to the GitBook documentation.