chore: Nest skill and protocol network permissions under network.enabled

[celia-oai]

Summary

Changes the permission profile shape from a bare network boolean to a nested object.

Before:

permissions:
  network: true

After:

permissions:
  network:
    enabled: true

This also updates the shared Rust and app-server protocol types so PermissionProfile.network is no longer Option<bool>, but Option<NetworkPermissions> with enabled: Option<bool>.

What Changed

• Updated PermissionProfile in codex-rs/protocol/src/models.rs:
  • pub network: Option<bool> -> pub network: Option<NetworkPermissions>
• Added NetworkPermissions with:
  • pub enabled: Option<bool>
• Changed emptiness semantics so network is only considered empty when enabled is None
• Updated skill metadata parsing to accept permissions.network.enabled
• Updated core permission consumers to read network.enabled.unwrap_or(false) where a concrete boolean is needed
• Updated app-server v2 protocol types and regenerated schema/TypeScript outputs
• Updated docs to mention additionalPermissions.network.enabled