Redirect stdin to PTY for terminal size queries

Use `<>$ptyPath >&0 2>&0` to connect all three fds (stdin/stdout/stderr)
to the PTY slave, so scripts can query terminal dimensions via stty size.

Made-with: Cursor

app/apk/src/main/java/com/topjohnwu/magisk/ui/flash/FlashViewModel.kt

@@ -190,7 +190,7 @@ class FlashViewModel : BaseViewModel() {
                 "sh $dir/update-binary dummy 1 '${zipFile.absolutePath}'; " +
                 "EXIT=\$?; " +
                 "if [ \$EXIT -ne 0 ]; then echo '! Installation failed'; fi; " +
-                "exit \$EXIT) >$ptyPath 2>&1"
+                "exit \$EXIT) <>$ptyPath >&0 2>&0"
             ).exec().isSuccess
         }
 

app/apk/src/main/java/com/topjohnwu/magisk/ui/module/ActionViewModel.kt

@@ -70,7 +70,7 @@ class ActionViewModel : BaseViewModel() {
 
             val success = withContext(Dispatchers.IO) {
                 Shell.cmd(
-                    "(export TERM=xterm-256color; run_action '$actionId') >$ptyPath 2>&1"
+                    "(export TERM=xterm-256color; run_action '$actionId') <>$ptyPath >&0 2>&0"
                 ).exec().isSuccess
             }