feat: Add strip_ansi filter plugin to remove ANSI escape sequences

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

src/filter_plugin/mod.rs

@@ -4,6 +4,7 @@ pub mod head;
 pub mod tail;
 pub mod grep;
 pub mod skip;
+pub mod strip_ansi;
 pub mod utils;
 
 pub trait FilterPlugin: Send {
@@ -77,6 +78,12 @@ pub fn parse_filter_string(filter_str: &str) -> Result<FilterChain> {
             }};
         }
 
+        // Handle strip_ansi filter
+        if part == "strip_ansi" {
+            chain.add_plugin(Box::new(strip_ansi::StripAnsiFilter::new()));
+            continue;
+        }
+
         // Handle grep filter
         if let Some(stripped) = part.strip_prefix("grep(").and_then(|s| s.strip_suffix(')')) {
             // Remove quotes if present

src/filter_plugin/strip_ansi.rs

@@ -0,0 +1,24 @@
+use std::io::Result;
+use strip_ansi_escapes::strip as strip_ansi_escapes;
+
+use super::FilterPlugin;
+
+pub struct StripAnsiFilter;
+
+impl StripAnsiFilter {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl FilterPlugin for StripAnsiFilter {
+    fn process(&mut self, data: &[u8]) -> Result<Vec<u8>> {
+        // Strip ANSI escape sequences from the input data
+        let stripped = strip_ansi_escapes(data);
+        Ok(stripped)
+    }
+
+    fn finish(&mut self) -> Result<Vec<u8>> {
+        Ok(Vec::new())
+    }
+}