The v2026.6.19 Desktop starts its source backend through the host Python.
Windows cannot expose that process environment or working directory. Carry
the app's verified source root into the existing strict provenance check.
A PM update can leave a locked historical executable beside the current
command-file launcher. Settle the updated runtime through the command file and
use verbatim cmd.exe arguments so paths with spaces remain valid.
Verified with the focused Desktop smoke tests, the tests-js typecheck, syntax
checks, and a native Windows ARM command-file launch probe.
