Fix ps1 path casing on case-insensitive filesystems (Windows)

Use fs.readdir to find the actual activate.ps1 filename with correct
casing instead of checking hardcoded 'Activate.ps1'/'activate.ps1'.
On Windows, pathExists is case-insensitive so the wrong cased path
would be returned when the file has different casing.

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

Author: eleanorjboyd

src/managers/common/utils.ts

@@ -183,11 +183,14 @@ export async function getShellActivationCommands(binDir: string): Promise<{
     shellActivation.set(ShellConstants.KSH, [{ executable: '.', args: [path.join(binDir, `activate`)] }]);
     shellDeactivation.set(ShellConstants.KSH, [{ executable: 'deactivate' }]);
 
-    if (await fs.pathExists(path.join(binDir, 'Activate.ps1'))) {
-        shellActivation.set(ShellConstants.PWSH, buildPwshActivationCommands(path.join(binDir, 'Activate.ps1')));
-        shellDeactivation.set(ShellConstants.PWSH, [{ executable: 'deactivate' }]);
-    } else if (await fs.pathExists(path.join(binDir, 'activate.ps1'))) {
-        shellActivation.set(ShellConstants.PWSH, buildPwshActivationCommands(path.join(binDir, 'activate.ps1')));
+    // Use readdir to find the actual ps1 filename with correct casing.
+    // pathExists with a hardcoded name fails on case-insensitive filesystems (Windows)
+    // where 'activate.ps1' created by the user would match 'Activate.ps1' in the check,
+    // causing the returned path to have the wrong case.
+    const dirFiles = await fs.readdir(binDir).catch(() => [] as string[]);
+    const ps1File = dirFiles.find((f) => f.toLowerCase() === 'activate.ps1');
+    if (ps1File) {
+        shellActivation.set(ShellConstants.PWSH, buildPwshActivationCommands(path.join(binDir, ps1File)));
         shellDeactivation.set(ShellConstants.PWSH, [{ executable: 'deactivate' }]);
     }