fix(directus-client): secure preview credential handling

[remihuigen]

Summary

Make SSR authentication hydration resilient to transient refresh infrastructure failures while keeping resolution refresh-aware.

• SSR still attempts a refresh when the access token is expired or inside the refresh safety window.
• Successful refreshes rotate the session and hydrate the refreshed snapshot.
• Terminal refresh failures clear the session and hydrate the application as unauthenticated.
• Explicitly classified transient refresh failures fall back to the trusted sealed local snapshot without failing SSR.
• Authenticated upstream requests and explicit refresh/session endpoints retain strict refresh-aware behavior.
• Local snapshot reading remains expiry-tolerant and separate from currently usable credential resolution.

Make Directus preview and request credential handling explicit and safe.

• Session credentials now take precedence over preview tokens, followed by proxy credentials and anonymous access.
• Preview/version selection remains independent from credential selection, so preview URLs cannot replace an authenticated user identity.
• Preview query handling is disabled by default and requires explicit opt-in with client.preview.enabled: true.
• Existing preview-only, proxy-fallback, and version-preview behavior remains available when enabled.
• Updated tests, consumer documentation, skills, and Changesets for both behavior changes.

Validation

• corepack pnpm format
• corepack pnpm lint:fix
• corepack pnpm typecheck
• corepack pnpm test — 122 files, 697 tests
• corepack pnpm build
• corepack pnpm validate:packages
• corepack pnpm validate:docs

Stacked on #280

Closes #265
Closes #271
Closes #274

[github-actions]

🦋 Changeset detected

Latest commit: 4abe7a1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@onderwijsin/nuxt-directus-client	Minor
@onderwijsin/nuxt-directus-config	Minor
@onderwijsin/nuxt-directus-sitemaps	Patch
@onderwijsin/nuxt-directus-prerenderer	Patch

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