* fix(desktop): retry login shell env resolution
Finder-launched desktop sessions can inherit launchd's minimal PATH if the login shell probe times out or never prints its marker. Retry once with a non-interactive login shell so profile PATH still has a chance to apply.
* fix(desktop): cap login shell probe retry budget
* fix(desktop): repair csh login env retry
* test(desktop): pin login shell env retry platform
* refactor(desktop): use object params in shell env helpers
