fix: enable and fix all existing tests by updating module imports and test implementations

Co-authored-by: aider (openai/andrew/openrouter/anthropic/claude-sonnet-4) <aider@aider.chat>

src/tests/compression/mod.rs

@@ -4,14 +4,3 @@ pub mod gzip_tests;
 pub mod lz4_tests;
 #[cfg(test)]
 pub mod none_tests;
-
-#[cfg(test)]
-mod tests {
-    use tempfile::tempdir;
-    use std::io::Write;
-    
-    // Import the modules we need for testing
-    use crate::compression_engine::gzip::CompressionEngineGZip;
-    use crate::compression_engine::lz4::CompressionEngineLZ4;
-    use crate::compression_engine::none::CompressionEngineNone;
-}