fix: remove unused digest field and mutable process

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

src/config.rs

@@ -170,9 +170,6 @@ impl Settings {
             config_builder = config_builder.set_override("compression_plugin.name", compression.as_str())?;
         }
         
-        if let Some(digest) = &args.item.digest {
-            config_builder = config_builder.set_override("digest", digest.as_str())?;
-        }
         
         if !args.item.meta_plugins.is_empty() {
             let meta_plugins: Vec<std::collections::HashMap<String, String>> = args.item.meta_plugins

src/meta_plugin/program.rs

@@ -96,7 +96,7 @@ impl MetaPlugin for MetaPluginProgram {
 
     fn finalize(&mut self) -> Result<()> {
         debug!("META: Finalizing program plugin");
-        if let Some(mut process) = self.process.take() {
+        if let Some(process) = self.process.take() {
             // Close stdin to signal end of input
             drop(self.writer.take());