Each vendor's system presets serialize into a single <vendor>.opc built at
package time, and a shipped build carries that file alone — the profile JSON
and its sub-file tree are pruned. The vendor loader, the setup wizard's profile
list and the resource installer all read a vendor through its cache, falling
back to parsing whenever one is absent, stale or unreadable, so the cache stays
an optimization and never a source of truth. Caches hold presets in source form
and resolve inheritance at load, through the same code the JSON path uses.
