Fix

crates/nazarick-core/src/llm/traits.rs

@@ -1,5 +1,6 @@
 // nazarick-core/src/llm/traits.rs
 
+use std::str::FromStr;
 use crate::types::Result;
 use crate::llm::types::{LlmRequest, LlmResponse};
 
@@ -13,13 +14,14 @@ pub enum SkillFormat {
     None,
 }
 
-impl SkillFormat {
-    /// Parsed aus config.toml String
-    pub fn from_str(s: &str) -> Self {
+impl FromStr for SkillFormat {
+    type Err = ();
+
+    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
         match s {
-            "tool_use" => Self::ToolUse,
-            "none"     => Self::None,
-            _          => Self::Xml,  // default
+            "tool_use" => Ok(Self::ToolUse),
+            "none"     => Ok(Self::None),
+            _          => Ok(Self::Xml),
         }
     }
 }