fix(cloud/submit,agents): strip NULs in submit output; skip PATH check for builtin cloud

- Sanitize submit --wait output by removing embedded NULs before printing
- Adjust executor PATH check to also skip when family==cloud and no custom config
- Builds clean with ./build-fast.sh

codex-rs/cloud-tasks/src/lib.rs

@@ -1631,6 +1631,8 @@ async fn run_submit(args: crate::cli::SubmitArgs) -> anyhow::Result<()> {
                     }
                     None => out.push_str("No diff available.\n"),
                 }
+                // Sanitize any embedded NULs that could corrupt downstream consumers.
+                let out = out.replace('\0', "");
                 print!("{}", out);
                 return Ok(());
             }

codex-rs/core/src/agent_tool.rs

@@ -697,7 +697,9 @@ async fn execute_model_with_permissions(
     // Proactively check for presence of external command before spawn when not
     // using the current executable fallback. This avoids confusing OS errors
     // like "program not found" and lets us surface a cleaner message.
-    if family != "codex" && family != "code" && !command_exists(&command) {
+    if !(family == "codex" || family == "code" || (family == "cloud" && config.is_none()))
+        && !command_exists(&command)
+    {
         return Err(format!("Required agent '{}' is not installed or not in PATH", command));
     }