Add OverFast API client utility

[Copilot]

Interface to the OverFast API for fetching Overwatch hero, map, and player data at runtime, with localStorage persistence and portrait hashing for image matching.

Types (src/types.d.ts)

• API response types: OverFastHero, OverFastMap, OverFastPlayerResult, OverFastPlayerSearchResponse
• Storage types: StoredHero (includes portraitHash), StoredMap, OverFastStore (schema-versioned)

API Client (src/utils/overfastApi.ts)

• fetchHeroes(), fetchMaps(), searchPlayers(name) — typed fetch wrappers for /heroes, /maps, /players
• hashPortraitFromUrl(url) — loads portrait image cross-origin and computes dhash (same algorithm as imageRecognition.ts)
• updateOverFastData() — fetches heroes + maps, hashes all portraits via Promise.all, persists to vowt_overfast_data
• loadOverFastData() / clearOverFastData() — localStorage read/clear with Date reviver

// Fetch and cache all data
const store = await updateOverFastData();
// store.heroes[0].portraitHash → "6b2b17451147b400" (ready for hamDist comparison)

// Load from cache
const cached = loadOverFastData();

Tests

26 tests covering all exported functions — fetch mocking, image loading, canvas mocking, error handling, URL encoding, Date revival, corrupted data.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add data fetching from OverFast API</issue_title>
<issue_description>We should fetch hero list, in-game character portraits, and maps list, at runtime via OverFast API.

Store to persistent memory and only update when prompted by user via a new button on the UI.
Hero portraits should be hashed before storing, ready for image matching.</issue_description>

<agent_instructions>No need to fully integrate in this branch/PR, just make an implementation that provides an interface to the API. This should include a new util file, typings, handling received data, etc.

Allowlist configured to:

• https://overfast-api.tekrop.fr/openapi.json
• https://overfast-api.tekrop.fr/heroes
• https://overfast-api.tekrop.fr/maps
• https://overfast-api.tekrop.fr/players</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Custom agent used: solid-developer
Agent specialising in SolidJS web development

• Fixes Add data fetching from OverFast API #43

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