Add openapi-to-rust to sdk category

[lightsofapollo]

Adds openapi-to-rust — a Rust code generator that produces strongly-typed structs, async HTTP clients, and SSE streaming clients from OpenAPI 3.1 specs.

Why it fills a gap in the existing list

The current Rust entries in tools.yaml are mostly OpenAPI 3.0 parsers/serializers (openapi3-rust, keycloak-openapi). There isn't a Rust 3.1 client generator with first-class streaming support listed. openapi-to-rust covers:

• OpenAPI 3.1 — objects, arrays, enums, oneOf/anyOf/allOf, discriminated unions
• HTTP client generation — async clients with retry, tracing, and auth middleware
• SSE streaming — reconnecting Server-Sent Events clients with typed event unions (built for LLM APIs like OpenAI and Anthropic)
• Smart \$ref resolution — handles circular references and deep nesting
• TOML config — declarative alternative to the Rust API
• MIT licensed, on crates.io and docs.rs

Entry

```yaml

• name: openapi-to-rust
  description: Generate strongly-typed Rust structs, async HTTP clients, and SSE streaming clients from OpenAPI 3.1 specs. Supports discriminated unions, anyOf/oneOf, allOf composition, circular $refs, and reconnecting SSE — built for LLM APIs (OpenAI, Anthropic) and similar.
  github: https://github.com/gpu-cli/openapi-to-rust
  v3: true
  language: Rust
  category: sdk
  uuid: 2bf0f104-2acd-41ef-9fd4-4fa32e35eb50
  downloads: 0
  ```

Format follows the same minimal style used in recent add-tool PRs (#88, #95) — auto-populated fields (stars/forks/etc.) left for the upstream tooling.

[gemini-code-assist]

Code Review

This pull request adds the openapi-to-rust tool to the tools.yaml data file. Feedback was provided to move the new entry to its correct alphabetical position based on the GitHub URL to maintain consistency with the project's sorting logic.