Support Unix socket allowlists in macOS sandbox (#17654)

## Changes

Allows sandboxes to restrict overall network access while granting
access to specific unix sockets on mac.

## Details

- `codex sandbox macos`: adds a repeatable `--allow-unix-socket` option.
- `codex-sandboxing`: threads explicit Unix socket roots into the macOS
Seatbelt profile generation.
- Preserves restricted network behavior when only Unix socket IPC is
requested, and preserves full network behavior when full network is
already enabled.

## Verification

- `cargo test -p codex-cli -p codex-sandboxing`
- `cargo build -p codex-cli --bin codex`
- verified that `codex sandbox macos --allow-unix-socket /tmp/test.sock
-- test-client` grants access as expected

codex-rs/sandboxing/src/manager.rs

@@ -9,10 +9,6 @@ use crate::policy_transforms::EffectiveSandboxPermissions;
 use crate::policy_transforms::effective_file_system_sandbox_policy;
 use crate::policy_transforms::effective_network_sandbox_policy;
 use crate::policy_transforms::should_require_platform_sandbox;
-#[cfg(target_os = "macos")]
-use crate::seatbelt::MACOS_PATH_TO_SEATBELT_EXECUTABLE;
-#[cfg(target_os = "macos")]
-use crate::seatbelt::create_seatbelt_command_args_for_policies;
 use codex_network_proxy::NetworkProxy;
 use codex_protocol::config_types::WindowsSandboxLevel;
 use codex_protocol::models::PermissionProfile;
@@ -208,14 +204,19 @@ impl SandboxManager {
             SandboxType::None => (os_argv_to_strings(argv), None),
             #[cfg(target_os = "macos")]
             SandboxType::MacosSeatbelt => {
-                let mut args = create_seatbelt_command_args_for_policies(
-                    os_argv_to_strings(argv),
-                    &effective_file_system_policy,
-                    effective_network_policy,
+                use crate::seatbelt::CreateSeatbeltCommandArgsParams;
+                use crate::seatbelt::MACOS_PATH_TO_SEATBELT_EXECUTABLE;
+                use crate::seatbelt::create_seatbelt_command_args;
+
+                let mut args = create_seatbelt_command_args(CreateSeatbeltCommandArgsParams {
+                    command: os_argv_to_strings(argv),
+                    file_system_sandbox_policy: &effective_file_system_policy,
+                    network_sandbox_policy: effective_network_policy,
                     sandbox_policy_cwd,
                     enforce_managed_network,
                     network,
-                );
+                    extra_allow_unix_sockets: &[],
+                });
                 let mut full_command = Vec::with_capacity(1 + args.len());
                 full_command.push(MACOS_PATH_TO_SEATBELT_EXECUTABLE.to_string());
                 full_command.append(&mut args);