Add exec-server network policy callback types (#34620)

## What changed

- Define the `network/policyRequest` RPC payloads for associating a network request with a process and returning an `allow`, `deny`, or `ask` decision.
- Cover HTTP, HTTPS CONNECT, and SOCKS5 TCP/UDP requests, with shared size limits for callback fields.
- Add the backward-compatible `requestPolicyDecisions` remote proxy option so executors can opt in to sending policy decisions to clients.
- Re-export the new protocol types from `codex-exec-server`.

## Testing

- Verify the request and decision JSON shapes.
- Verify that the proxy opt-in is omitted and defaults to `false` for legacy configurations, while an enabled value round-trips.

GitOrigin-RevId: 65b0a0723d1abb6e4f504a41d3a0dd41f5f21bf7

codex-rs/network-proxy/src/remote_config.rs

@@ -66,6 +66,9 @@ pub struct RemoteNetworkProxyConfig {
     pub domains: Option<NetworkDomainPermissions>,
     pub unix_sockets: Option<NetworkUnixSocketPermissions>,
     pub allow_local_binding: bool,
+    /// Whether the executor sends domain policy decisions back to the client.
+    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+    pub request_policy_decisions: bool,
 }
 
 impl RemoteNetworkProxyConfig {
@@ -88,6 +91,7 @@ impl RemoteNetworkProxyConfig {
             domains: config.domains.clone(),
             unix_sockets: config.unix_sockets.clone(),
             allow_local_binding: config.allow_local_binding,
+            request_policy_decisions: false,
         })
     }
 

codex-rs/network-proxy/src/remote_config_tests.rs

@@ -118,3 +118,26 @@ fn launch_config_materializes_audit_and_execution_attribution() {
     assert_eq!(state.environment_id(), Some("remote"));
     assert_eq!(state.execution_id().as_deref(), Some("execution-1"));
 }
+
+#[test]
+fn policy_decision_callback_opt_in_is_backward_compatible() {
+    let mut config =
+        RemoteNetworkProxyConfig::from_effective_config(&NetworkProxyConfig::default())
+            .expect("supported remote config");
+    let legacy = serde_json::to_value(&config).expect("serialize legacy config");
+    assert_eq!(legacy.get("requestPolicyDecisions"), None);
+    assert!(
+        !serde_json::from_value::<RemoteNetworkProxyConfig>(legacy)
+            .expect("deserialize legacy remote config")
+            .request_policy_decisions
+    );
+
+    config.request_policy_decisions = true;
+    let enabled = serde_json::to_value(&config).expect("serialize callback-enabled config");
+    assert_eq!(enabled["requestPolicyDecisions"], true);
+    assert_eq!(
+        serde_json::from_value::<RemoteNetworkProxyConfig>(enabled)
+            .expect("deserialize callback-enabled config"),
+        config
+    );
+}