Feature Request: Multi-Dimensional Scoring, Custom Group Sizes, and Advanced Categorical Constraints

### Problem Statement
The current solver implementation is strictly limited to single-dimensional optimization. Specifically:
1. **Single Score Optimization:** Groups are balanced using exactly one continuous variable (\Score\).
2. **Inflexible Separation:** Separation constraints are limited to a single boolean flag (appending \*\ to names). Real-world scenarios often require balancing multiple categorical tiers (e.g., IPPT results: Gold, Silver, Pass).
3. **Rigid Group Sizing:** The mathematical model forces even group sizes via \
um_people // num_groups\. Asymmetric constraints (e.g., configuring two groups of 3 and two groups of 5) are impossible.
4. **No Inclusion Constraints:** There is no mechanism to force designated participants into the same group.

### Proposed Solution

... [rest of the body] ...

### Implementation Progress
- [ ] #39 Performance Optimization: Advanced Solver Roadmap