Add Sharpe API definition

[rishabhng]

Adds Sharpe's official OpenAPI definition to the directory.

The API fits this repository as a machine-readable OpenAPI 3.0 definition for crypto market intelligence, including derivatives, market data, arbitrage, narratives, exchange listings, and signals. I added the APIs.guru metadata fields and repaired two response references in the submitted copy so the definition validates while keeping the official origin URL.

Spec origin: https://www.sharpe.ai/openapi.json
Website/docs: https://www.sharpe.ai/docs/free-api
Validation: npx --yes @apidevtools/swagger-cli validate APIs/sharpe.ai/1.0.0/openapi.yaml and git diff --check pass.
Linear: SHA-65

Disclosure: I work on Sharpe.

[gemini-code-assist]

Code Review

This pull request introduces the initial OpenAPI 3.0.0 specification for the Sharpe API, providing a comprehensive set of endpoints for crypto market data, including derivatives, arbitrage opportunities, and market signals. Feedback on the specification highlighted an inconsistency where endpoints supporting a CSV format via the FormatParam parameter lacked a corresponding text/csv content type in their successful response definitions.

[gemini-code-assist]

The FormatParam parameter allows for a csv response format, but the 200 response definition only includes application/json. Please add text/csv to the content section for this and other endpoints that use FormatParam to accurately reflect the API's capabilities.

content:
  application/json:
    schema:
      "$ref": "#/components/schemas/SuccessEnvelope"
  text/csv:
    schema:
      type: string

[rishabhng]

Thanks for catching this. I updated the OpenAPI definition so every endpoint that accepts format=csv now documents text/csv alongside the existing application/json 200 response.

The JSON response schemas are unchanged; this only makes the documented response content types match the API behavior. Please let me know if you prefer a shared CSV response component instead of repeating text/csv per endpoint.