refactor: update meta plugins to use new trait interface

Co-authored-by: aider (openai/andrew/openrouter/mistralai/mistral-medium-3.1) <aider@aider.chat>

src/meta_plugin/system.rs

@@ -60,13 +60,14 @@ impl MetaPlugin for CwdMetaPlugin {
         true
     }
     
-    fn finalize(&mut self, _conn: &Connection) -> Result<()> {
+    fn finalize(&mut self) -> Result<PluginResponse> {
         // Since we save during initialize(), return Ok to avoid duplicate saves
-        Ok(())
+        Ok(PluginResponse::default())
     }
 
-    fn update(&mut self, _data: &[u8], _conn: &Connection) {
+    fn update(&mut self, _data: &[u8]) -> Result<PluginResponse> {
         // No update needed
+        Ok(PluginResponse::default())
     }
 
     fn meta_name(&self) -> String {