fix: resolve import errors in test modules and remove unused variables

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

src/tests/db/meta_tests.rs

@@ -1,8 +1,8 @@
 #[cfg(test)]
 mod tests {
     use tempfile::TempDir;
-    use keep::db;
-    use keep::db::Meta;
+    use crate::db;
+    use crate::db::Meta;
 
     #[test]
     fn test_database_meta_operations() {
@@ -25,11 +25,11 @@ mod tests {
         assert!(insert_result.is_ok());
         
         // Try to get meta for non-existent item
-        let item = keep::db::Item {
+        let item = crate::db::Item {
             id: 999, // Non-existent item
             ts: chrono::Utc::now(),
             size: 0,
-            compression: keep::compression_engine::CompressionType::None,
+            compression: crate::compression_engine::CompressionType::None,
         };
         
         let metas = db::get_item_meta(&conn, &item);