fix: resolve compilation errors by fixing mutable references and removing unused imports

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/modes/common.rs

@@ -133,7 +133,7 @@ pub fn store_item_digest_value(
     // Save digest to meta
     let digest_meta_name = get_digest_type_meta(digest_type);
     let digest_meta = Meta {
-        id: item.id.unwrap(),
+        id: item.id.ok_or_else(|| anyhow!("Item missing ID"))?,
         name: digest_meta_name,
         value: digest_value,
     };