fix: address valid PR review findings

Fix two valid issues identified in automated code review:

1. Fix OAuth callback AppState to preserve pending_approvals
   - Clone existing pending_approvals instead of creating empty HashMap
   - Prevents loss of shell approval requests during OAuth flow

2. Add validation to activate_kubeconfig
   - Check that kubeconfig ID exists before activation
   - Return error if ID not found to prevent silent failure

Invalid findings clarified:
- Ollama retry logic is correct (anyhow::bail exits immediately)
- systemctl classification already handles subcommands correctly
  (lines 230-239: status/is-active/is-enabled are Tier 1)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src-tauri/src/commands/integrations.rs

@@ -325,6 +325,7 @@ pub async fn initiate_oauth(
         let app_data_dir = app_state.app_data_dir.clone();
         let integration_webviews = app_state.integration_webviews.clone();
         let mcp_connections = app_state.mcp_connections.clone();
+        let pending_approvals = app_state.pending_approvals.clone();
 
         tokio::spawn(async move {
             let app_state_for_callback = AppState {
@@ -333,9 +334,7 @@ pub async fn initiate_oauth(
                 app_data_dir,
                 integration_webviews,
                 mcp_connections,
-                pending_approvals: Arc::new(tokio::sync::Mutex::new(
-                    std::collections::HashMap::new(),
-                )),
+                pending_approvals,
             };
             while let Some(callback) = callback_rx.recv().await {
                 tracing::info!("Received OAuth callback for state: {}", callback.state);

src-tauri/src/commands/shell.rs

@@ -97,12 +97,17 @@ pub fn activate_kubeconfig(id: String, state: State<'_, AppState>) -> Result<(),
         .map_err(|e| format!("Failed to deactivate configs: {e}"))?;
 
     // Activate the specified config
-    db.execute(
+    let rows_updated = db
+        .execute(
             "UPDATE kubeconfig_files SET is_active = 1 WHERE id = ?1",
             params![&id],
         )
         .map_err(|e| format!("Failed to activate config: {e}"))?;
 
+    if rows_updated == 0 {
+        return Err(format!("Kubeconfig with id '{}' not found", id));
+    }
+
     Ok(())
 }