v0.1.0

First release of the official Nim client for the UniRate API.

• Stdlib-only (std/httpclient + std/json) — zero third-party dependencies
• Full-parity client: 11 procs covering all 9 canonical methods
• Typed exception hierarchy (UniRateError base + Auth/RateLimit/InvalidCurrency/InvalidDate + APIError with status for 403/503)
• Injectable Transport for offline testing
• 20 mock tests + 6 env-gated free-tier live tests
• Nim 1.6+; compile with -d:ssl for HTTPS

Install: nimble install unirate_api