Adds a Biome noRestrictedImports rule scoped to core/, viewer/, and
editor/ packages. Framework code must reach node-specific behavior via
nodeRegistry.get(kind), never via direct import. The @pascal-app/nodes
package doesn't exist yet (lands in the next commit) so the rule is a
no-op today; codifies the boundary ahead of node bundles.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
