feat: implement buffer size limit and early metadata storage for binary plugin

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

src/meta_plugin/binary.rs

@@ -26,19 +26,11 @@ impl BinaryMetaPlugin {
         }
     }
     
-}
-
-impl MetaPlugin for BinaryMetaPlugin {
-    fn is_internal(&self) -> bool {
-        true
-    }
-    
-    fn finalize(&mut self, conn: &Connection) -> Result<()> {
-        // Save the binary detection result when finalizing, after all data has been collected
+    fn save_metadata(&mut self, conn: &Connection) -> Result<()> {
         if !self.is_saved {
             if let Some(item_id) = self.item_id {
-                let is_binary = is_binary(&self.buffer);
-                let value = if is_binary { "true".to_string() } else { "false".to_string() };
+                let is_binary_result = is_binary(&self.buffer);
+                let value = if is_binary_result { "true".to_string() } else { "false".to_string() };
                 
                 // Save to database immediately using central output handler
                 let _ = output_metadata(conn, item_id, &self.meta_name, value, &self.output_names);
@@ -48,13 +40,34 @@ impl MetaPlugin for BinaryMetaPlugin {
         }
         Ok(())
     }
+}
 
-    fn update(&mut self, data: &[u8], _conn: &Connection) {
-        // Only collect up to max_buffer_size
+impl MetaPlugin for BinaryMetaPlugin {
+    fn is_internal(&self) -> bool {
+        true
+    }
+    
+    fn finalize(&mut self, conn: &Connection) -> Result<()> {
+        // Save the binary detection result when finalizing, if not already saved
+        self.save_metadata(conn)
+    }
+
+    fn update(&mut self, data: &[u8], conn: &Connection) {
+        // If we've already saved the metadata, no need to collect more data
+        if self.is_saved {
+            return;
+        }
+        
+        // Add data to buffer
         let remaining_capacity = self.max_buffer_size.saturating_sub(self.buffer.len());
         if remaining_capacity > 0 {
             let bytes_to_copy = std::cmp::min(data.len(), remaining_capacity);
             self.buffer.extend_from_slice(&data[..bytes_to_copy]);
+            
+            // If we've reached the buffer limit, save the metadata immediately
+            if self.buffer.len() >= self.max_buffer_size {
+                let _ = self.save_metadata(conn);
+            }
         }
     }
 
@@ -72,6 +85,11 @@ impl MetaPlugin for BinaryMetaPlugin {
             if let Some(size) = max_buffer_size.as_u64() {
                 self.max_buffer_size = size as usize;
             }
+        } else if let Some(max_buffer_size) = options.get("max_buffer") {
+            // Also support "max_buffer" for backward compatibility
+            if let Some(size) = max_buffer_size.as_u64() {
+                self.max_buffer_size = size as usize;
+            }
         }
         
         if let Some(outputs) = options.get("outputs") {