feat: implement search utility functions and add tests for Anime prov…

[heiznerd]

…iders

[Copilot]

Pull request overview

This PR introduces shared search normalization/ranking utilities and updates Anime providers to use them for higher-quality, more stable search results (including Vietnamese diacritics handling and common “label” stripping).

Changes:

• Added cleanSearchQuery and rankSearchResults utilities for consistent query cleaning, normalization, and result ranking.
• Updated AnimeVietsub and Anime47 providers to use centralized ranking + improved fallback behavior and timeout control for browser-based fetches.
• Added a new checks/search-check.mts script to validate the ranking behavior and provider search fallbacks.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
scrapers/search-utils.ts	Adds reusable query cleaning + normalized ranking logic (accent-aware, label-stripping, stable ordering).
scrapers/providers/animevietsub.ts	Uses the new utilities to merge/rank search candidates and refines Playwright timeout handling.
scrapers/providers/anime47.ts	Uses the new utilities for better search relevance and adjusts API/HTML fallback behavior.
checks/search-check.mts	Adds coverage for the new utilities and provider search fallback/ranking behavior.

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