katex-memo.ts (added in 112cad59b) imports hast-util-from-html-isomorphic,
hast-util-to-text, remark-math, katex, and unist-util-visit-parents but
those were never added to apps/desktop/package.json. They were silently
resolving via @streamdown/math at the workspace root, which broke the
moment `npm i --prefix apps/desktop` ran with the per-workspace lockfile
because that install only consults apps/desktop/package.json. Add them
as direct deps, plus unified/vfile/@types/hast for the type imports.
Also delete apps/desktop/package-lock.json — root package.json declares
workspaces: ["apps/*"], so npm manages all lockfile state at the root.
The stale per-app lockfile is what made `npm i --prefix apps/desktop`
diverge from the workspace install in the first place and left an empty
apps/desktop/node_modules/@assistant-ui/ stub that Vite's dep optimizer
then tried (and failed) to open at @assistant-ui/core/dist/internal.js.