[SaladDay]

Executes the official Environment network field for hosted Sessions, within the deployment cap.

• disabled: the sandbox reaches only Core and the Session's model provider for its whole life, packages and setup included. No Core check on packages or setup.
• restricted: exact host names only. A domain equal to a cap domain goes to Egress.PrivateDomains; otherwise, when the cap allows the public internet, to the new Egress.Domains (public addresses only); otherwise Session creation fails with sandbox_network_outside_cap and param set to that allowed_domains entry. The same check runs again when an allocation derives its Egress.
• Admission: disabled and restricted on a hosted Environment need the current Provider's NetworkSupport.Restrict (sandbox_network_unsupported); self_hosted keeps accepting only enabled. The blanket rejection is gone.
• microsandbox: Domains get domain allow rules after deny private, so only public answers pass. E2B: allow_out also lists Domains (not Public denies everything else).
• Docs (EN + zh): environments, OpenAI compatibility (leading-dot allowed_domains entries are rejected, unspecified officially), Harness capabilities row, Sandbox Provider protocol.

Existing validation already rejects wildcards, a leading dot, and disabled with allowed_domains, and accepts upper case.

Not verified live: E2B allow_out with a public domain on a real sandbox (the SDK documents hostnames; the Core host already uses one).

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