fix(adb): refuse transfers when destination existence is unknown

Own ADB command failure facts once and interpret only the clean empty test false result as absence. Preserve unknown probe output and reuse parsed facts for package refusals.

Related: #4574

docs/adb-device-analysis.md

@@ -153,8 +153,10 @@ and during shutdown.
 - **Mutations are explicit.** `push_adb_file`, `install_adb_package`, and
   `uninstall_adb_package` declare `mutatesTarget` and never run implicitly:
   pushes check for existing device files before transfer and refuse them
-  unless `overwrite` is set. The check is not atomic, so a different process
-  can create the path before `adb push` writes it. When available, the device's
+  unless `overwrite` is set. A failed or unexpected existence probe stops
+  transfer even with `overwrite`; only a clean `test -e` exit of 1 with no
+  output is interpreted as absence. The check is not atomic, so a different
+  process can create the path before `adb push` writes it. When available, the device's
   `sha256sum` verifies the transfer; installs preserve the
   device's `Failure [...]` reason verbatim.
 - **Producer identity stays attached.** Every result embeds the producing