An OpenAPI description of the Fusion API

New features

• An OpenAPI 3.1 description of the read-only api.ipor.io endpoints is published at /openapi.json and /openapi.yaml. It gives the meaning, unit and nullability of every field. An AI agent given that URL can call the API without further explanation.
• The API docs start from GET /v2/fusion/vaults, every Fusion vault on every chain with its current statistics in one small file, and GET /v2/fusion/markets, current supply and borrow rates for every market.
• A new section, Which APY to use, explains netApy, grossApy, apy, underlyingAssetApy and the reward fields, and which one is the after-fee yield.
• The API docs list how often each history bucket is regenerated: 7d every 5 minutes, 30d once a day, 1y every 7 days and all every 30 days. The merge rule for all now includes 1y.
• The v1 endpoints are listed as legacy and deprecated, each with the v2 endpoint to use in its place.