refactor(auth): setup convenience for OAuth

Signed-off-by: kjuulh <contact@kjuulh.io>

como_auth/src/lib.rs

@@ -1,4 +1,5 @@
 pub use introspection::IntrospectionConfigClap;
+use oauth::{OAuth, ZitadelConfig};
 
 mod introspection;
 mod oauth;
@@ -47,7 +48,16 @@ pub struct ZitadelClap {
     pub token_url: Option<String>,
 }
 
-impl AuthClap {}
+impl TryFrom<AuthClap> for OAuth {
+    type Error = anyhow::Error;
+
+    fn try_from(value: AuthClap) -> Result<Self, Self::Error> {
+        match value.engine {
+            AuthEngine::Noop => Ok(OAuth::new_noop()),
+            AuthEngine::Zitadel => Ok(OAuth::from(ZitadelConfig::try_from(value.zitadel)?)),
+        }
+    }
+}
 
 #[cfg(test)]
 mod test {