Update ai-agents skills bundle (v57.2) (#6568)

Automated agent-skills bundle for **v57.2** (RFC-0026): this tag's
skill tree (with the freshly rolled `trace_processor` wrapper
bundled inside it at `plugins/perfetto/skills/perfetto/bin/`) and
the per-agent manifests.
The version pin `refs/ai-agent-tag/v57.2` already points at this
bundle commit (`b18ced5adab398f899f1f5f4214bd2852e17b1f0`). On merge,
`ai-agents` advances and
installed agents pick up the update through their normal channels.

Co-authored-by: perfetto-automation[bot] <perfetto-automation-github-app@google.com>