Feat | Add support for OpenAPI 3.1 [CU-86b7bdpnw]

[matiasperrone-exo]

Task:

Ref: https://app.clickup.com/t/86b7bdpnw (CU-86b7bdpnw)

[martinquiroga-exo]

@matiasperrone-exo please review comments.

[matiasperrone-exo]

@martinquiroga-exo please review again:

Files changed:

• backend/openapi_schema.py (new) — MarketingAutoSchema with get_tags() (checks OAuth2Authentication in authentication_classes) and get_auth() (returns [] for public, [{'OAuth2': []}] for private)
• backend/settings.py — updated DEFAULT_SCHEMA_CLASS to backend.openapi_schema.MarketingAutoSchema, removed POSTPROCESSING_HOOKS and global SECURITY.
• backend/openapi_hooks.py (deleted)

Note:

• The check is OAuth2Authentication in authentication_classes rather than emptiness, because public views inherit DRF's default SessionAuthentication/BasicAuthentication from global settings.