Fix noctx lint warnings

[JamieMagee]

Replace http.NewRequest with http.NewRequestWithContext and net.Listen with net.ListenConfig{}.Listen to satisfy the noctx linter.

The startup code in nuget_feed.go uses context.Background() since there's no incoming request context to propagate. Test files do the same.

[Copilot]

Pull request overview

This PR fixes noctx linter warnings by replacing deprecated functions with their context-aware equivalents. The changes update http.NewRequest to http.NewRequestWithContext and net.Listen to net.ListenConfig{}.Listen, both using context.Background() which is appropriate for test code and initialization code where no upstream context exists.

Changes:

• Replace deprecated http.NewRequest with http.NewRequestWithContext(context.Background(), ...) in tests and startup code
• Replace deprecated net.Listen with net.ListenConfig{}.Listen(context.Background(), ...) in test setup
• Add context import to all modified files

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
proxy_test.go	Updated test helpers to use context-aware HTTP request and network listen functions
logging_test.go	Updated test case to use http.NewRequestWithContext
internal/handlers/nuget_feed.go	Updated NuGet feed initialization code to use context-aware HTTP requests
internal/handlers/git_server_test.go	Updated multiple test cases to use http.NewRequestWithContext