Fuzzy matcher unit tests in pytest suite

[askmy-stack]

Background

Identified during OSS audit v2 of meridian.

Problem Statement

Only script test exists.

Proposed Solution

tests/unit/test_fuzzy_matcher.py.

Acceptance Criteria

• Implementation complete
• Tests pass
• Documented in README or docs/

Files / Modules Affected

src/entity_resolution/fuzzy_matcher.py

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Suggested labels: priority:medium, difficulty:intermediate, category:testing
Milestone: v2.0-features
OSS Audit: Master Backlog v2