Ship one preset cache per vendor in place of the profile JSONs

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.

.gitattributes

@@ -1,2 +1,7 @@
 # Set the default behavior, in case people don't have core.autocrlf set.
 * text=auto
+
+# Shell scripts are run by Git Bash on Windows CI, which cannot read a script
+# with CRLF line endings: it fails on the first line. Windows checkouts default
+# to core.autocrlf=true, so keep these LF whatever the platform.
+*.sh text eol=lf