docs: add Daytona to backend lists in docs

Signed-off-by: rovle <lovre.pesut@gmail.com>

CONTRIBUTING.md

@@ -153,7 +153,7 @@ hermes-agent/
 │   ├── skill_tools.py            # Skill search, load, manage
 │   └── environments/             # Terminal execution backends
 │       ├── base.py                   # BaseEnvironment ABC
-│       ├── local.py, docker.py, ssh.py, singularity.py, modal.py
+│       ├── local.py, docker.py, ssh.py, singularity.py, modal.py, daytona.py
 │
 ├── gateway/                  # Messaging gateway
 │   ├── run.py                    # GatewayRunner — platform lifecycle, message routing, cron