explicitly prevents subgraphs from making an api call since they don't
have docs, this was previously reliant on a non-ok resolution
also doesn't try returning anything that has contenttype of text/html to
prevent the markdown renderer from crashing
## Summary
- short-circuit blueprint/subgraph nodes in help: skip doc fetch and
return the node description, avoiding SPA fallback responses
- guard node help fetch against HTML/SPA fallbacks using content-type
checks; treat them as missing and trigger the existing description
fallback
- keep base URL logic unchanged for non-blueprint nodes
## Testing
- pnpm typecheck
- pnpm lint:fix
- pnpm test:unit
This PR cleans up the base-layer utilities so they no longer pull
renderer or workbench code. The renderer-only `isPrimitiveNode` guard
now lives in `src/renderer/utils/nodeTypeGuards.ts`, and the node
help/model/ordering helpers have moved into `src/workbench/utils`. All
affected services, stores, scripts, and tests were updated to import
from the new locations.
The idea is to reduce the number of Base→Renderer/Base→Workbench edges
(higher scoped base/common utils should not import from
renderer/workbench layers).
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6621-refactor-move-renderer-dependent-utils-into-workbench-scope-2a36d73d36508167aff0fc8a22202d7f)
by [Unito](https://www.unito.io)
