feat(ssr): add Next shared CSS output

[tenphi]

Summary

• add withTastyNext() at @tenphi/tasty/ssr/next-config
• emit eager configured globals to one content-hashed shared stylesheet
• keep component rules and all route-specific hook artifacts in the streaming TastyRegistry path
• add immutable caching for Next server deployments while preserving static-export compatibility
• preserve basePath, existing env/headers, monorepo roots, CSP nonces, and safe CSS URL semantics

Shared vs route-specific

The shared file contains built-in/custom @property, tokens and presets, @font-face, @counter-style, native @function, and configured globalStyles.

Component chunks plus route calls to useGlobalStyles, useRawCSS, useKeyframes, useProperty, useFontFace, useCounterStyle, and useFunction remain route-specific. Configured keyframes stay lazy.

Verification

• production Next.js 16.2.7 App Router build with Turbopack
• direct / and /about loads: exactly one shared link plus the correct route CSS
• Home → About client navigation: shared link retained; only newly needed route CSS/keyframes injected
• computed tokens, global body styles, component styles, and animation verified in Chromium
• generated asset returned Cache-Control: public, max-age=31536000, immutable
• pnpm typecheck
• pnpm lint
• pnpm format:check
• pnpm build
• pnpm check:test-only
• pnpm knip
• pnpm test (2,204 tests)
• pnpm size

Includes a minor changeset.

[github-actions]

📦 Snapshot release

Published 0.0.0-snapshot.5ee6468.

pnpm add @tenphi/tasty@0.0.0-snapshot.5ee6468