Task 11 of Phase 1 Bank Reconciliation. Adds the brain that ranks
candidate journal-item matches for a bank statement line.
Pass 1 — SQL filter (done by caller's _fetch_candidates).
Pass 2 — Statistical scoring: weighted blend of amount-delta,
partner pattern fit, and precedent similarity.
Pass 3 — Optional AI re-rank when an LLM provider is configured;
gracefully no-ops when provider missing, prompt module not
yet present (Task 20), or the JSON response is malformed.
Pass 4 — Persistence (handled by engine.suggest_matches).
Returns top-K ScoredCandidate dataclasses with per-feature scores
exposed for transparency and future learning.
7 new tests added; full module suite green (51 tests, 0 failures).
Made-with: Cursor
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