feat: stork integration

[pp346]

Summary

• Introduces a Stork PriceAPIDataHandler that queries /v1/prices/latest with comma-separated asset IDs.

Details

• Parses Stork’s integer price strings into floats and returns current UTC timestamps.
• Registers the provider in APIQueryHandlerFactory.
• API
  • Request: GET https://rest.jp.stork-oracle.network/v1/prices/latest?assets=<ID1,ID2,...>
  • Response: JSON map of asset_id -> price (string), scaled by 10^18.
  • Parsing: Converts price string to big.Float and divides by 1e18; unknown assets are ignored.
  • Timestamps: Uses time.Now().UTC() (provider timestamp not propagated).
• Config
  • New provider name: stork_api.
  • DefaultAPIConfig: Enabled, Atomic=true, Timeout/Interval=3s, ReconnectTimeout=2s, MaxQueries=1.
  • Authentication: Authorization header populated from env var STORK_API_KEY.
• Implementation
  • Caches requested tickers during CreateURL to map returned asset IDs back to ProviderTicker.
  • Error handling:
    • JSON decode failure → unresolved for all tickers (ErrorFailedToDecode).
    • Price parse failure → unresolved for that ticker (ErrorFailedToParsePrice).
    • Missing response for a requested ticker → unresolved (ErrorNoResponse).
• Factory
  • Adds stork_api branch to instantiate the new API data handler.

Risk & Impact

• Low risk: additive provider; no changes to existing providers or schemas.
• Operational: requires configuring STORK_API_KEY when enabling this provider.
• Security: introduces API key usage via Authorization header.

Testing

• New unit tests:
  • URL creation: empty, single, multiple assets.
  • Response parsing: valid single/multiple, bad JSON, bad/empty price, missing/null data, no responses.
  • Numeric edges: hex literal, very small (1), very large, zero.
  • Verifies timestamps are set to “now” and unresolved errors are surfaced.