Implementation of the localize_atoms tool.

Returns the closed atom collection for a named kind — locales, calendars, currencies, languages, scripts, territories, number systems, etc. Each atom comes with its display name where one is cheaply available (currencies, territories) so an agent can pick the right code without a second round-trip.

Backed by the existing Localize.X.known_* accessors. The collections themselves are interned at app start by Localize.Supervisor (see intern_supplemental_atoms/0 in Localize's source), so this tool's cost is the inspect and (optional) display-name lookup per atom.