test(logging): add tests for FilteredLogger message discard

[adcondev]

🎯 What: Added unit tests for FilteredLogger's message discarding mechanism to ensure it behaves correctly when verbose mode is on/off.
📊 Coverage: Added tests covering verbose=true/false scenarios, testing discarding of non-critical messages, and testing preservation of critical messages. Also refactored FilteredLogger to take an io.Writer instead of an *os.File to make testing simpler without actual files.
✨ Result: Increased test coverage for the logging package, ensuring correct log filtering behavior.

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PR created automatically by Jules for task 11542656801431102939 started by @adcondev

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[github-actions]

⚡ Benchmark Results

⚠️ No benchmarks found in the current codebase.

To add benchmarks, create functions starting with Benchmark in *_test.go files.

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 13.63636% with 19 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/logging/logging.go	21.42%	11 Missing ⚠️
internal/logging/rotation.go	0.00%	6 Missing ⚠️
internal/auth/auth.go	0.00%	2 Missing ⚠️

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