fix: use correct stream type when initializing stderr log file

[gumruyanzh]

Summary

• Fix typo in Environment.zig line 184: .stdout -> .stderr
• The --log-error CLI option was being silently ignored

Problem

In Environment.init(), the stderr log file was being initialized with .stdout instead of .stderr:

// Before (line 184):
const stderr = try getLogFile(.stdout, options.options);
// After:
const stderr = try getLogFile(.stderr, options.options);

This caused getLogFile to use options.log (the stdout log path) instead of options.@"log-error" (the stderr log path) for the error log file. Both log streams ended up with the same destination configuration, and the --log-error option was effectively ignored.

Test plan

• zig build succeeds
• zig build test --summary all - all tests pass

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