feat: Implement registry for meta plugins

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

src/meta_plugin/exec.rs

@@ -225,3 +225,47 @@ impl MetaPlugin for MetaPluginExec {
         &mut self.options
     }
 }
+use crate::meta_plugin::register_meta_plugin;
+use crate::meta_plugin::MetaPluginType;
+
+// Register the plugin at module initialization time
+#[ctor::ctor]
+fn register_exec_plugin() {
+    register_meta_plugin(MetaPluginType::Exec, |options, outputs| {
+        // For exec type, we need to parse the command from options
+        let mut program_name = String::new();
+        let mut args = Vec::new();
+        let mut meta_name = MetaPluginType::Exec.to_string();
+        let mut split_whitespace = true;
+        
+        if let Some(opts) = &options {
+            if let Some(command_value) = opts.get("command") {
+                if let Some(command_str) = command_value.as_str() {
+                    let parts: Vec<&str> = command_str.split_whitespace().collect();
+                    if !parts.is_empty() {
+                        program_name = parts[0].to_string();
+                        args = parts[1..].iter().map(|s| s.to_string()).collect();
+                    }
+                }
+            }
+            // Handle other options if needed
+            if let Some(split_value) = opts.get("split_whitespace") {
+                if let Some(split_bool) = split_value.as_bool() {
+                    split_whitespace = split_bool;
+                }
+            }
+            if let Some(name_value) = opts.get("name") {
+                if let Some(name_str) = name_value.as_str() {
+                    meta_name = name_str.to_string();
+                }
+            }
+        }
+        
+        Box::new(MetaPluginExec::new(&program_name, 
+                                    args.iter().map(|s| s.as_str()).collect(), 
+                                    meta_name, 
+                                    split_whitespace, 
+                                    options, 
+                                    outputs))
+    });
+}