chore: close pipe on non-pty processes (#9369)

Closing the STDIN of piped process when starting them to avoid commands
like `rg` to wait for content on STDIN and hangs for ever

codex-rs/core/src/unified_exec/mod.rs

@@ -136,6 +136,7 @@ struct ProcessEntry {
     call_id: String,
     process_id: String,
     command: Vec<String>,
+    tty: bool,
     last_used: tokio::time::Instant,
 }