Update OpenAPI to 3.1.1

[mshriver]

Together with the python client library, update the OpenAPI spec to 3.1.1

Here is an evaluation from sonnet 4 on what the update would encompass.

I don't believe it about using a const for result instead of enum, there are specific result types to enumerate.

=== OpenAPI 3.1.1 Migration Analysis ===
Current version: 3.0.0

Features that could benefit from OpenAPI 3.1.1:

1. Nullable fields (could use JSON Schema null types): 15
   Examples:
   - Result.component
   - Result.env
   - Result.run_id
   - Result.project_id
   - Run.source
   ... and 10 more

2. Enhanced $ref usage opportunities:
   - OpenAPI 3.1.1 allows $ref in more locations
   - Could potentially use $ref for examples, descriptions, etc.

3. Schema composition opportunities:
   - OpenAPI 3.1.1 has better support for oneOf/anyOf/allOf
   - Could be used for polymorphic schemas or union types

4. JSON Schema 2020-12 features:
   - Better validation rules
   - More precise type definitions
   - Conditional schemas (if/then/else)

5. Enum fields (could use const for single values): 1
   Examples:
   - Result.result

6. Format fields (could use new JSON Schema formats): 28
   Examples:
   - Result.id: uuid
   - Result.run_id: uuid
   - Result.project_id: uuid
   - Run.id: uuid
   - Run.project_id: uuid

=== Migration Recommendations ===
1. Update openapi version to 3.1.1
2. Replace nullable: true with type: ["string", "null"] (or appropriate type)
3. Consider using JSON Schema 2020-12 features for better validation
4. Review enum usage - consider const for single values
5. Update tooling to support OpenAPI 3.1.1
6. Test thoroughly with Connexion 3.x compatibility

[mshriver]

This is actually blocked by connexion, as even connexion 3.3 doesn't support validation.

There are a few open PRs against connexion trying to indroduce the support but they're stale.

[RonnyPfannschmidt]

Thats reading like it's trying to optimize preexisting structure mistakes