fix(ui): add rename_all_fields to HelixEvent so exit_code serializes as exitCode

Serde's rename_all on an enum only renames variant names (Output→output,
Done→done), not fields inside struct variants. Without rename_all_fields,
Done { exit_code } serializes as "exit_code" in JSON, but the frontend
reads msg.data.exitCode — always undefined — making every command block
show status "error" regardless of the real exit code.

Fix: add rename_all_fields = "camelCase" at the container level (serde
≥1.0.185, we use 1.0.228) so exit_code → exitCode in the Done variant.

https://claude.ai/code/session_01E7C1r4saaKwguu88r6sqt4

Author: claude

ui/src-tauri/src/commands.rs

@@ -5,7 +5,7 @@ use tokio::io::{AsyncBufReadExt, BufReader};
 use tokio::process::Command;
 
 #[derive(Clone, Serialize)]
-#[serde(rename_all = "camelCase", tag = "event", content = "data")]
+#[serde(rename_all = "camelCase", rename_all_fields = "camelCase", tag = "event", content = "data")]
 pub enum HelixEvent {
     Output { stream: String, line: String },
     Done { exit_code: i32 },