fix: always prepend separator when appending noConfigScripts to PATH

EnvironmentVariableCollection.append() performs a literal string concatenation
and does not insert a path separator. The previous heuristic checked
process.env.PATH on the extension host and skipped the separator when that PATH
already ended with one. However, the PATH used by the integrated terminal can
differ from the extension host's PATH, so this check could incorrectly drop the
separator and glue the noConfigScripts directory onto the last entry of the
user's PATH (e.g. C:\Program Files\jreleaser\c:\Users\...\noConfigScripts).

Always prepend the separator. A trailing empty PATH entry (if the user's PATH
already ended with one) is harmless on both Windows and POSIX shells.

Fixes #1637

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: wenytang-ms

src/noConfigDebugInit.ts

@@ -93,12 +93,12 @@ export async function registerNoConfigDebug(
     const noConfigScriptsDir = path.join(extPath, 'bundled', 'scripts', 'noConfigScripts');
     const pathSeparator = process.platform === 'win32' ? ';' : ':';
 
-    // Check if the current PATH already ends with a path separator to avoid double separators
-    const currentPath = process.env.PATH || '';
-    const needsSeparator = currentPath.length > 0 && !currentPath.endsWith(pathSeparator);
-    const pathValueToAppend = needsSeparator ? `${pathSeparator}${noConfigScriptsDir}` : noConfigScriptsDir;
-
-    collection.append('PATH', pathValueToAppend);
+    // EnvironmentVariableCollection.append() does literal string concatenation and does
+    // not insert a separator. Always prepend one so we never glue our directory onto the
+    // last entry of the user's PATH. We cannot rely on process.env.PATH ending with a
+    // separator, since the terminal's PATH may differ from the extension host's PATH.
+    // A trailing empty PATH entry (when PATH already ends with the separator) is harmless.
+    collection.append('PATH', `${pathSeparator}${noConfigScriptsDir}`);
 
     // create file system watcher for the debuggerAdapterEndpointFolder for when the communication port is written
     const fileSystemWatcher = vscode.workspace.createFileSystemWatcher(