What Problem This Solves

waitForChildProcess attaches data listeners to child.stdout and child.stderr, but does not attach error listeners. If either stream emits an error event, the unhandled error can crash the OpenClaw process even though the child process exit has already been observed.

Why This Change Was Made

Add no-op error handlers to both stdout and stderr streams before the data handlers. Stream read errors are treated as non-fatal because the child process error/exit/close handlers report the real outcome. The new listeners are also removed in cleanup to avoid leaks.

User Impact

More robust child process waiting: transient stream read errors no longer crash the agent runtime.

Evidence

• Added a regression test in src/agents/utils/child-process.test.ts that creates a fake child with PassThrough stdout/stderr, emits error events on both streams, and verifies waitForChildProcess still resolves successfully.
• Verified the test fails on main with Error: stdout read failed and passes with this fix.
• oxlint passes on the changed files.