feat: add finalization state tracking to meta plugins

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

src/meta_plugin/binary.rs

@@ -6,6 +6,7 @@ use crate::meta_plugin::{MetaPlugin, MetaPluginResponse};
 pub struct BinaryMetaPlugin {
     buffer: Vec<u8>,
     max_buffer_size: usize,
+    is_finalized: bool,
     base: crate::meta_plugin::BaseMetaPlugin,
 }
 
@@ -31,6 +32,7 @@ impl BinaryMetaPlugin {
         BinaryMetaPlugin {
             buffer: Vec::new(),
             max_buffer_size,
+            is_finalized: false,
             base,
         }
     }
@@ -41,8 +43,23 @@ impl BinaryMetaPlugin {
 }
 
 impl MetaPlugin for BinaryMetaPlugin {
+    fn is_finalized(&self) -> bool {
+        self.is_finalized
+    }
+    
+    fn set_finalized(&mut self, finalized: bool) {
+        self.is_finalized = finalized;
+    }
 
     fn update(&mut self, data: &[u8]) -> MetaPluginResponse {
+        // If already finalized, don't process more data
+        if self.is_finalized {
+            return MetaPluginResponse {
+                metadata: Vec::new(),
+                is_finalized: true,
+            };
+        }
+        
         // Calculate how much data we can still accept
         let remaining_capacity = self.max_buffer_size.saturating_sub(self.buffer.len());
         if remaining_capacity > 0 {
@@ -67,6 +84,9 @@ impl MetaPlugin for BinaryMetaPlugin {
             ) {
                 metadata.push(meta_data);
             }
+            
+            // Mark as finalized
+            self.is_finalized = true;
         }
 
         let is_finalized = !metadata.is_empty();
@@ -77,6 +97,14 @@ impl MetaPlugin for BinaryMetaPlugin {
     }
 
     fn finalize(&mut self) -> MetaPluginResponse {
+        // If already finalized, don't process again
+        if self.is_finalized {
+            return MetaPluginResponse {
+                metadata: Vec::new(),
+                is_finalized: true,
+            };
+        }
+        
         let mut metadata = Vec::new();
 
         // Save the binary detection result when finalizing
@@ -91,6 +119,9 @@ impl MetaPlugin for BinaryMetaPlugin {
         ) {
             metadata.push(meta_data);
         }
+        
+        // Mark as finalized
+        self.is_finalized = true;
 
         MetaPluginResponse {
             metadata,