KPIs V2 beta release

This release adds KPI V2 support to the simulator and aligns the export pipeline with the new KPI naming contract.

Highlights:

• New KPI V2 metrics for EV behaviour, electrical-service constraints, and community-market settlement.
• KPI exports now use evaluate_v2() by default, so the UI and CSV export path are aligned with the new contract.
• Added Sphinx documentation for KPI V2, including the KPI tree, usage examples, and the community-market toggle behaviour.
• Expanded regression coverage for electrical-service validation, KPI formulas, boolean parsing, and export behaviour.
• Internal loading, runtime, and building orchestration were refactored to support the KPI pipeline cleanly.

Notes:

evaluate() is still available for legacy workflows.
New workflows should use evaluate_v2() and the updated KPI export path.