Restructure solver.py with prompt caching in ServingSolver, improve
results dataclass, update pipeline chaining, and modernize test suite.
Replace hardcoded hardware values with constants throughout.
- Add typed Pydantic result models (Layer A) replacing dict returns
- Add canonical Wall taxonomy registry (walls.py) as single source of truth
- Add Pipeline composer (Layer C) for solver chaining with explain()/run()
- Rename domains: Metabolism→Node, Skeleton→Data, Mind→Algorithm, World→Fleet, Meta→Analysis
- Rename MetabolismSolver→EfficiencySolver and MetabolismResult→EfficiencyResult
- Update all solver classes with walls tuple referencing canonical wall numbers
- Convert all dict access patterns to typed attribute access across codebase
