feat: add default_options method to all meta plugins

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

src/meta_plugin/digest.rs

@@ -65,6 +65,10 @@ impl MetaPlugin for DigestSha256MetaPlugin {
     fn default_outputs(&self) -> Vec<String> {
         vec!["digest_sha256".to_string()]
     }
+    
+    fn default_options(&self) -> std::collections::HashMap<String, serde_yaml::Value> {
+        std::collections::HashMap::new()
+    }
 }
 
 
@@ -115,6 +119,10 @@ impl MetaPlugin for ReadTimeMetaPlugin {
     fn default_outputs(&self) -> Vec<String> {
         vec!["read_time".to_string()]
     }
+    
+    fn default_options(&self) -> std::collections::HashMap<String, serde_yaml::Value> {
+        std::collections::HashMap::new()
+    }
 }
 
 #[derive(Debug, Clone, Default)]
@@ -167,4 +175,8 @@ impl MetaPlugin for ReadRateMetaPlugin {
     fn default_outputs(&self) -> Vec<String> {
         vec!["read_rate".to_string()]
     }
+    
+    fn default_options(&self) -> std::collections::HashMap<String, serde_yaml::Value> {
+        std::collections::HashMap::new()
+    }
 }