docs: rebuild OpenAPI 3.1.0 spec from source — 34 paths, 27 schemas

Complete rewrite of the OpenAPI specification generated from actual
route handlers, transforms.ts, query-parser-v2.ts, and auth.ts.

Covers all 35 public operations across 10 tag groups: Health,
Reference Data, Events, Odds, Opportunities, Streaming, Account,
Deep Links, Futures, and Game State. Includes reusable parameters,
response envelopes, rate limit headers, tier documentation, and
SSE event type reference.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Mlaz-code