feat: add warning message for both blocklist and allowlist are set

[zyfy29]

close #3847

[Copilot]

Pull Request Overview

This PR adds a warning message when both environment variable blocklist and allowlist are configured simultaneously. When both LIMA_SHELLENV_BLOCK and LIMA_SHELLENV_ALLOW are set, the system now warns the user and ignores the blocklist to avoid configuration conflicts.

• Modified getBlockList() and getAllowList() functions to return boolean flags indicating if the environment variables are explicitly set
• Added logic in FilterEnvironment() to detect when both lists are configured and emit a warning
• Updated all test cases to handle the new return signature with boolean flags

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
pkg/envutil/envutil.go	Modified functions to return set flags and added warning logic for conflicting configurations
pkg/envutil/envutil_test.go	Updated test cases to handle new function signatures and verify set flags

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[jandubois]

Thanks, LGTM