[feat] Final classification calculation API

[erikbayerlein]

Epic: #71 (Arguição e Entrevista)
Use Case: #66

Fase 2 — Implementação posterior à fase de inscrição.

Description

Calculate final candidate ranking based on all evaluation components.

Acceptance Criteria

• For master's: combines IRA, validated CV score, and interview score using the edital formula.
• For doctoral: additionally includes research project score.
• Generates ranked list of candidates per theme.
• Respects minimum score thresholds (nota ≥ 7.0 in interview for approval).
• Secretary can trigger classification calculation.
• Results are stored and can be published.