fix: resolve clippy warnings (field_reassign_with_default, large_enum_variant, too_many_arguments)

Author: RoyLin

core/src/agent_api.rs

@@ -805,9 +805,10 @@ impl Agent {
         // Inject agent system prompt via the extra slot (same as task tool).
         if opts.prompt_slots.is_none() {
             if let Some(ref prompt) = def.prompt {
-                let mut slots = crate::prompts::SystemPromptSlots::default();
-                slots.extra = Some(prompt.clone());
-                opts.prompt_slots = Some(slots);
+                opts.prompt_slots = Some(crate::prompts::SystemPromptSlots {
+                    extra: Some(prompt.clone()),
+                    ..Default::default()
+                });
             }
         }
 

core/src/orchestrator/events.rs

@@ -9,6 +9,7 @@ use serde::{Deserialize, Serialize};
 /// Orchestrator 事件 - 统一的事件类型
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "event_type", rename_all = "snake_case")]
+#[allow(clippy::large_enum_variant)]
 pub enum OrchestratorEvent {
     /// SubAgent 启动
     SubAgentStarted {

core/src/orchestrator/wrapper.rs

@@ -25,6 +25,7 @@ pub struct SubAgentWrapper {
 }
 
 impl SubAgentWrapper {
+    #[allow(clippy::too_many_arguments)]
     pub fn new(
         id: String,
         config: SubAgentConfig,