feat: update meta plugin constructors to accept options and outputs

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

src/meta_plugin/magic.rs

@@ -16,16 +16,48 @@ pub struct MagicFileMetaPlugin {
 }
 
 impl MagicFileMetaPlugin {
-    pub fn new() -> MagicFileMetaPlugin {
+    pub fn new(
+        options: Option<std::collections::HashMap<String, serde_yaml::Value>>,
+        outputs: Option<std::collections::HashMap<String, serde_yaml::Value>>,
+    ) -> MagicFileMetaPlugin {
+        // Start with default options
+        let mut final_options = Self::default_options();
+        if let Some(opts) = options {
+            for (key, value) in opts {
+                final_options.insert(key, value);
+            }
+        }
+        
+        // Start with default outputs
+        let mut final_outputs = std::collections::HashMap::new();
+        let default_outputs = Self::default_outputs();
+        for output_name in default_outputs {
+            final_outputs.insert(output_name.clone(), serde_yaml::Value::String(output_name));
+        }
+        if let Some(outs) = outputs {
+            for (key, value) in outs {
+                final_outputs.insert(key, value);
+            }
+        }
+        
+        let max_buffer_size = final_options.get("max_buffer_size")
+            .and_then(|v| v.as_u64())
+            .unwrap_or(4096) as usize;
+        
         MagicFileMetaPlugin {
             buffer: Vec::new(),
-            max_buffer_size: 4096, // Same as BinaryMetaPlugin
+            max_buffer_size,
             is_saved: false,
             item_id: None,
             cookie: None,
-            outputs: std::collections::HashMap::new(),
+            outputs: final_outputs,
         }
     }
+    
+    pub fn new_simple() -> MagicFileMetaPlugin {
+        Self::new(None, None)
+    }
+}
 
     fn get_magic_result(&self, flags: CookieFlags) -> io::Result<String> {
         // Use the existing cookie and just change flags