registryMounts
The mounts in the registry's codebase, as its pages call them: each mirrored release's (@alice.dev/geo 1.2.0, its
library's page, under Libraries) and each mirrored codebase's (@alice.dev/notes, its page, under Codebases).
Read again by refreshMounts.
export const registryMounts = new Map<string, { label: string; href: string; tab: string }>()