Remove unused variables

Backend/src/plugin_runtime/events.rs

@@ -66,7 +66,7 @@ pub fn emit_from_plugin(plugin_id: &str, name: &str, payload: Value) {
 pub fn emit_to_plugins(origin_plugin_id: Option<&str>, name: &str, payload: Value) {
     let _ = payload;
     if let Ok(lock) = registry().lock() {
-        let _targets: Vec<String> = lock
+        let _ = lock
             .subs
             .iter()
             .filter_map(|(plugin_id, events)| {
@@ -78,6 +78,6 @@ pub fn emit_to_plugins(origin_plugin_id: Option<&str>, name: &str, payload: Valu
                 }
                 Some(plugin_id.clone())
             })
-            .collect();
+            .collect::<Vec<_>>();
     }
 }

Backend/src/plugin_runtime/manager.rs

@@ -480,7 +480,7 @@ impl PluginRuntimeManager {
         }
 
         trace!("start_plugin_spec: creating new instance");
-        let instance = self.create_instance(&spec)?;
+        let instance = Self::create_instance(&spec)?;
         debug!("start_plugin_spec: instance created, ensuring running");
         instance.ensure_running()?;
 
@@ -521,10 +521,7 @@ impl PluginRuntimeManager {
     }
 
     /// Creates a runtime instance for a resolved plugin spec.
-    fn create_instance(
-        &self,
-        spec: &ModuleRuntimeSpec,
-    ) -> Result<Arc<dyn PluginRuntimeInstance>, String> {
+    fn create_instance(spec: &ModuleRuntimeSpec) -> Result<Arc<dyn PluginRuntimeInstance>, String> {
         create_runtime_instance(spec.spawn.clone())
     }
 

Backend/src/plugin_runtime/node_instance.rs

@@ -206,7 +206,7 @@ impl NodePluginRuntimeInstance {
     /// # Returns
     /// - `Ok(String)` with absolute path to bundled node runtime.
     /// - `Err(String)` when bundled runtime path is unavailable.
-    fn node_executable(&self) -> Result<String, String> {
+    fn node_executable() -> Result<String, String> {
         let Some(path) = plugin_paths::node_executable_path() else {
             return Err(
                 "bundled node runtime is unavailable; plugin execution requires app-bundled node"
@@ -222,7 +222,7 @@ impl NodePluginRuntimeInstance {
     /// - `Ok(NodeRpcProcess)` when startup succeeds.
     /// - `Err(String)` when process startup or init RPC fails.
     fn spawn_process(&self) -> Result<NodeRpcProcess, String> {
-        let node_exec = self.node_executable()?;
+        let node_exec = Self::node_executable()?;
         info!(
             "plugin runtime: starting node plugin '{}' via '{}'",
             self.spawn.plugin_id, node_exec