refactor: replace SanitizeMode::from_str with From<&str> impl

Address Gemini review feedback: use idiomatic From trait instead of
a custom from_str method, which also removes the clippy
should_implement_trait allow.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: geofflittle

src/helpers/modelarmor.rs

@@ -377,23 +377,23 @@ mod tests {
 
     #[test]
     fn test_sanitize_mode_from_str_warn() {
-        assert_eq!(SanitizeMode::from_str("warn"), SanitizeMode::Warn);
-        assert_eq!(SanitizeMode::from_str("WARN"), SanitizeMode::Warn);
-        assert_eq!(SanitizeMode::from_str("Warn"), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from("warn"), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from("WARN"), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from("Warn"), SanitizeMode::Warn);
     }
 
     #[test]
     fn test_sanitize_mode_from_str_block() {
-        assert_eq!(SanitizeMode::from_str("block"), SanitizeMode::Block);
-        assert_eq!(SanitizeMode::from_str("BLOCK"), SanitizeMode::Block);
-        assert_eq!(SanitizeMode::from_str("Block"), SanitizeMode::Block);
+        assert_eq!(SanitizeMode::from("block"), SanitizeMode::Block);
+        assert_eq!(SanitizeMode::from("BLOCK"), SanitizeMode::Block);
+        assert_eq!(SanitizeMode::from("Block"), SanitizeMode::Block);
     }
 
     #[test]
     fn test_sanitize_mode_from_str_unknown_defaults_to_warn() {
-        assert_eq!(SanitizeMode::from_str(""), SanitizeMode::Warn);
-        assert_eq!(SanitizeMode::from_str("invalid"), SanitizeMode::Warn);
-        assert_eq!(SanitizeMode::from_str("stop"), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from(""), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from("invalid"), SanitizeMode::Warn);
+        assert_eq!(SanitizeMode::from("stop"), SanitizeMode::Warn);
     }
 
     #[test]

src/main.rs

@@ -201,7 +201,7 @@ async fn run() -> Result<(), GwsError> {
         .or_else(|| std::env::var("GOOGLE_WORKSPACE_CLI_SANITIZE_TEMPLATE").ok());
 
     let sanitize_mode = std::env::var("GOOGLE_WORKSPACE_CLI_SANITIZE_MODE")
-        .map(|v| helpers::modelarmor::SanitizeMode::from_str(&v))
+        .map(|v| helpers::modelarmor::SanitizeMode::from(v.as_str()))
         .unwrap_or(helpers::modelarmor::SanitizeMode::Warn);
 
     let sanitize_config = parse_sanitize_config(sanitize_template, &sanitize_mode)?;

src/sanitize.rs

@@ -65,13 +65,12 @@ impl Default for SanitizeConfig {
     }
 }
 
-impl SanitizeMode {
+impl From<&str> for SanitizeMode {
     /// Parses a string into a `SanitizeMode`.
     ///
     /// * "block" (case-insensitive) -> `Block`
     /// * Any other value -> `Warn` (safe default)
-    #[allow(clippy::should_implement_trait)]
-    pub fn from_str(s: &str) -> Self {
+    fn from(s: &str) -> Self {
         match s.to_lowercase().as_str() {
             "block" => SanitizeMode::Block,
             _ => SanitizeMode::Warn,