Update $match API reference to match current implementation

[paynejd]

Summary

• Fix incorrect parameter defaults (numCandidates: 5000→3000, kNearest: 5→100) and ranges
• Add missing query parameters: brief, encoder_model, reranker
• Add missing body parameters: target_repo (alternative to URL), filter (locale + faceted filtering)
• Fix target_repo_url cardinality from 1..1 to 0..1, rows.synonyms type to accept string or list
• Document missing response fields: search_normalized_score, search_rerank_score, algorithm, search_confidence
• Add match_type scoring logic explanation for all search modes (token, semantic, semantic+reranker)
• Add authentication & access requirements section
• Fix broken JSON examples (syntax errors, mismatched data) with realistic responses
• Remove misleading includeSearchMeta=true (automatic for $match)
• Add Example Request 3 demonstrating semantic + reranker + locale filter

Companion API PR: OpenConceptLab/oclapi2#824

Test plan

• Build docs locally (make html) and review rendered match page
• Verify all parameter tables render correctly in Sphinx
• Confirm JSON examples are valid and realistic
• Check navigation/toctree still includes match entry

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