Made the extension module work on MacOS

[alex-an-dor]

Hello! Genuinely interested to make this module work on MacOS as I have a usecase for it

The list of changes as per the commit message:

• replaced PtrToStringAuto with PtrToStringBSTR for cross-platform compatibility (reason: https://stackoverflow.com/questions/60404847/are-you-able-to-use-ptrtostringauto-to-decrypt-a-secure-string-in-powershell-7-o)
• added IsWindows/$PSVersionTable check to avoid hardcoding op.exe
• PtrToStringBSTR is used in the tests too - tests pass
• bumped extension module version
• also accidentlly may have ran Powershell formatter on the whole psm1 file

Tests were ran under MacOS Sequoia 15.5:

> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      7.5.2
PSEdition                      Core
GitCommitId                    7.5.2
OS                             Darwin 24.5.0 Darwin Kernel Version 24.5.0: Tue Apr 22 19:54:33 PDT 2025; root:xnu-11417.121.6~2/RELEASE_ARM64_T8122
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Test results:

> Invoke-Pester

Starting discovery in 5 files.
Discovery found 33 tests in 97ms.
Running tests.
[+] /Users/<...>/SecretManagement.1Password/tests/Get-Secret.Tests.ps1 29.15s (28.94s|150ms)
[+] /Users/<...>/SecretManagement.1Password/tests/Get-SecretInfo.Tests.ps1 20.35s (20.3s|43ms)
[+] /Users/<...>/SecretManagement.1Password/tests/Remove-Secret.Tests.ps1 8.37s (8.34s|21ms)
[+] /Users/<...>/SecretManagement.1Password/tests/Set-Secret.Tests.ps1 86.5s (86.45s|42ms)
[+] /Users/<...>/SecretManagement.1Password/tests/Test-SecretVault.Tests.ps1 4.5s (4.44s|43ms)
Tests completed in 148.88s
Tests Passed: 30, Failed: 0, Skipped: 3, Inconclusive: 0, NotRun: 0

@cdhunt if you want anything else to be done for this to be merged, I'll be glad to help out

[alex-an-dor]

@cdhunt @Ben-m-s genuinely sorry about the bump but any chance you could take a look? If you need any input from me, I'm ready to help