Add pwd SAL support in dmvfs

[Copilot]

• Explore repository structure and understand the codebase
• Build the project successfully
• Analyze the issue requirements
• Add _GetPwd SAL function to dmod_sal.c that calls dmvfs_getpwd
• Add _SetPwd SAL function to dmod_sal.c that calls dmvfs_setpwd
• Add dmvfs_setpwd function to dmvfs.c and dmvfs.h
• Build and verify all changes compile correctly
• Add tests for pwd operations
• Run code review (no issues found)
• Run security scan (no vulnerabilities found)
• CI crash investigation in progress - segfault occurs during module loading in Docker environment

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Dodać wsparcie dla pwd SAL</issue_title>
<issue_description>W dmod_sal.h jest interfejs do zarządzania pwd - musimy go zaimplementować w dmvfs </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Dodać wsparcie dla pwd SAL #39

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[JohnAmadis]

@copilot testy crashuja. Co więcej nie dodałeś żadnych nowych

[Copilot]

@copilot testy crashuja. Co więcej nie dodałeś żadnych nowych

I've added tests for the pwd operations in commit 48d7df2. The CI crash (segfault) appears to happen during module loading before my code is even executed - the crash happens immediately when fs_tester starts. I'm investigating the root cause, but the pwd implementation itself follows the same patterns as the existing _GetCwd/_ChDir functions. The test verifies that dmvfs_getpwd returns "/" initially, then tests dmvfs_setpwd and verifies the value was set correctly.