refactor: derive GooseMode string conversions with strum (#7706)

Signed-off-by: Adrian Cole <adrian@tetrate.io>

crates/goose/src/config/goose_mode.rs

@@ -1,26 +1,24 @@
-use std::str::FromStr;
-
 use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString, IntoStaticStr, VariantNames};
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
+#[derive(
+    Copy,
+    Clone,
+    Debug,
+    Eq,
+    PartialEq,
+    Serialize,
+    Deserialize,
+    Display,
+    EnumString,
+    IntoStaticStr,
+    VariantNames,
+)]
 #[serde(rename_all = "snake_case")]
+#[strum(serialize_all = "snake_case")]
 pub enum GooseMode {
     Auto,
     Approve,
     SmartApprove,
     Chat,
 }
-
-impl FromStr for GooseMode {
-    type Err = String;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "auto" => Ok(GooseMode::Auto),
-            "approve" => Ok(GooseMode::Approve),
-            "smart_approve" => Ok(GooseMode::SmartApprove),
-            "chat" => Ok(GooseMode::Chat),
-            _ => Err(format!("invalid mode: {}", s)),
-        }
-    }
-}