improve TestDeleteContext using temporary directories

[Manar-Elhabbal7]

Description

This PR fixes a brittle test case in cmd/context_test.go where TestDeleteContext was failing on
non-Unix-native filesystems (like NTFS/FAT).

The test previously relied on a static file path in ./testdata/, which caused issues when trying to set
and verify restrictive file permissions (0600). By switching to t.TempDir(), the test is now isolated,
environment-agnostic, and leaves no garbage files behind.

Changes

• Removed hardcoded testConfigFilePath constant.
• Added path/filepath to imports.
• Updated TestDeleteContext to generate a unique temporary directory and path for each execution.

Related issue(s) : #313

[Caesarsage]

Thanks @Manar-Elhabbal7

This has largely being addressed on master, the newer context tests use t.TempDir() and the remaining fixture creates its directory explicitly, so the clean-clone failure is gone. If a specific NTFS/FAT permission failure remains, a fresh repro against master would help; otherwise I believe this can be closed.