Support `OpenAPI v3.2.0`

**Describe the feature**
Since september 2025 there is OpenAPI [`v3.2.0`](https://github.com/OAI/OpenAPI-Specification/releases/tag/3.2.0)

The most noteworthy additions are the "QUERY" HTTP method and the top level `$self` field.

Would be cool if the project supports both :)

Here is the full spec: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.2.0.md

Start by comparing the project's OpenAPI support with the linked OpenAPI v3.2.0 specification, focusing on the QUERY HTTP method and top-level $self field. Trace the annotation processor's OpenAPI generation entry points, then verify that both additions are emitted and accepted by the project's existing checks.

Written by the indexing model from the issue text.