Add configurable API suffix

[sneridagh]

What changed

Adds a configurable API traversal suffix for Volto.

• Introduces config.settings.apiSuffix, with RAZZLE_API_SUFFIX as its environment-variable counterpart.
• Centralizes suffix resolution in getApiSuffix() and uses it across API URL formatting, backend URL expansion, authenticated resource requests, and sitemap requests.
• Keeps existing behavior by default: Volto continues to use /++api++.
• Gives an explicitly configured apiSuffix precedence over legacyTraverse.
• Supports an empty suffix (RAZZLE_API_SUFFIX='' or apiSuffix: '') to intentionally omit traversal.
• Hydrates RAZZLE_API_SUFFIX from window.env so seamless-mode runtime configuration stays consistent between SSR and browser requests.
• Adds feature Towncrier entries for both @plone/volto and @plone/types, and documents the new environment variable.

Why

Volto currently chooses only between the fixed /++api++ suffix and no suffix through legacyTraverse.
Deployments that expose the Plone API under another traversal suffix need a supported configuration option without relying on the legacy traversal switch.

Impact

Integrators can configure a nonstandard API traversal suffix through config.settings.apiSuffix or RAZZLE_API_SUFFIX.
The setting overrides legacyTraverse when present, while existing installations retain their current behavior when it is absent.

Validation

• pnpm --filter @plone/volto test --run src/helpers/Url/Url.test.js src/helpers/Api/Api.plone.rest.test.js src/helpers/Api/PloneBackendAPIResourceWithAuth.test.js
  • 109 tests passed.
• pnpm --filter @plone/types check:ts
  • passed.
• Prettier check passed for the changed source, type, documentation, and test files.
• Commit hooks passed, including package lint/format checks and the i18n check.
• pnpm --filter @plone/volto check:ts still reports existing unrelated typing errors in widget and Storybook files; no errors are associated with this change.

[read-the-docs-community]

Documentation build overview

📚 volto | 🛠️ Build #33702451 | 📁 Comparing a0f2fc9 against latest (7f1c249)

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2 files changed

± genindex.html
± configuration/environmentvariables.html