feat(app): harden cancellable LAPP turns

crates/nana-domain/src/lib.rs

@@ -830,6 +830,17 @@ pub struct UpdateLappSettingsRequest {
     pub model_id: String,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(rename_all = "camelCase")]
+pub struct LappConnectionTestResult {
+    pub ok: bool,
+    pub provider_id: String,
+    pub model_id: String,
+    pub message: String,
+    pub diagnostic_code: Option<String>,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(rename_all = "camelCase")]
@@ -844,6 +855,10 @@ pub enum TurnFailureCode {
     StaleNode,
     InvalidInput,
     InvalidModelOutput,
+    ProviderConfiguration,
+    ProviderCredentials,
+    ProviderRateLimited,
+    ProviderRejected,
     ProviderUnavailable,
     Cancelled,
     TimedOut,