feat: add content filtering options to content endpoints

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/services/async_item_service.rs

@@ -189,9 +189,6 @@ impl AsyncItemService {
         line_start: Option<usize>,
         line_end: Option<usize>,
     ) -> Result<(std::pin::Pin<Box<dyn tokio_stream::Stream<Item = Result<tokio_util::bytes::Bytes, std::io::Error>> + Send>>, String), CoreError> {
-        let _db = self.db.clone();
-        let _item_service = self.item_service.clone();
-
         // Use provided metadata to determine MIME type and binary status
         let mime_type = metadata
             .get("mime_type")