refactor: make candidate explicit in matching

[pashawkola33]

Summary

• add immutable CandidateMatchingProfile as the explicit candidate input boundary for deterministic scoring
• keep the existing two-argument scoring API as a compatibility path backed by the current legacy configured candidate
• add candidate-aware scoring so the same job can be scored against different candidate profiles without repository access

Scope

This is an architectural extraction only. It does not change scoring weights, bands, freshness semantics, zero-backend-evidence behavior, ingestion, persistence, migrations, filters, Mini App, Telegram, LLM, or resume generation.

Validation

• 97 focused tests passed
• 0 failures, 0 errors, 0 skipped
• git diff --check clean
• no production/rescore commands run

Follow-up

A later phase will introduce multi-user persistence and candidate-scoped matches. This PR intentionally does not wire the persistent JPA CandidateProfile into scoring yet.