GHSA-7xr2-q9vf-x4r5: OpenClaw: Symlink Traversal via IDENTITY.md appendFile in agents.create/update (Incomplete Fix for CVE-2026-32013)

OpenClaw has a symlink traversal vulnerability (symlink: a file that points to another file) in two API handlers (`agents.create` and `agents.update`) that use `fs.appendFile` to write to an `IDENTITY.md` file without checking if it's a symlink. An attacker can place a symlink in the agent workspace pointing to a sensitive system file (like `/etc/crontab`), and when these handlers run, they will append attacker-controlled content to that sensitive file, potentially allowing remote code execution. This is an incomplete fix for CVE-2026-32013, which only patched two other handlers but missed these two.