fix: update filter_plugin import paths and mark unused field

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

src/filter_plugin/tail.rs

@@ -4,14 +4,14 @@ use ringbuf::{HeapRb, Rb};
 
 pub struct TailBytesFilter {
     ring_buffer: HeapRb<u8>,
-    count: usize,
+    _count: usize,
 }
 
 impl TailBytesFilter {
     pub fn new(count: usize) -> Self {
         Self {
             ring_buffer: HeapRb::new(count),
-            count,
+            _count: count,
         }
     }
 }