Forward executor network policy decisions for auditing (#38670)

## What changed

- Add a best-effort `network/policyDecision` notification for final domain and non-domain policy decisions made by executor-local proxies.
- Validate notifications against the active process on the controller and emit audit events with controller-trusted session and execution metadata.
- Reserve outbound RPC capacity so audit notifications cannot block control messages, and expose valid `chatgpt-account-id` header values for audit attribution.

## Testing

- Cover notification serialization, proxy decision capture, executor-to-controller delivery, trusted metadata handling, and reserved RPC capacity.

GitOrigin-RevId: a39f96a6b3d9401c03d54eaef5b9a6d3fe0da78b

codex-rs/exec-server-protocol/src/network_policy.rs

@@ -4,6 +4,7 @@ use serde::Serialize;
 use crate::ProcessId;
 
 pub const NETWORK_POLICY_REQUEST_METHOD: &str = "network/policyRequest";
+pub const NETWORK_POLICY_DECISION_METHOD: &str = "network/policyDecision";
 pub const MAX_NETWORK_POLICY_HOST_BYTES: usize = 253;
 pub const MAX_NETWORK_POLICY_PROCESS_ID_BYTES: usize = 256;
 pub const MAX_NETWORK_POLICY_REASON_BYTES: usize = 1024;
@@ -23,6 +24,27 @@ pub struct ExecServerNetworkPolicyRequest {
     pub port: u16,
 }
 
+/// Reports an executor-local network policy decision to its authenticated controller.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct NetworkPolicyDecisionNotification {
+    pub process_id: ProcessId,
+    pub timestamp: String,
+    pub scope: String,
+    pub decision: String,
+    pub source: String,
+    pub reason: String,
+    pub protocol: ExecServerNetworkProtocol,
+    pub host: String,
+    pub port: u16,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub method: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub client: Option<String>,
+    #[serde(default)]
+    pub policy_override: bool,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "snake_case")]
 pub enum ExecServerNetworkProtocol {

codex-rs/exec-server-protocol/src/network_policy_tests.rs

@@ -3,6 +3,7 @@ use pretty_assertions::assert_eq;
 use super::ExecServerNetworkPolicyDecision;
 use super::ExecServerNetworkPolicyRequest;
 use super::ExecServerNetworkProtocol;
+use super::NetworkPolicyDecisionNotification;
 use super::NetworkPolicyRequestParams;
 use super::NetworkPolicyRequestResponse;
 use crate::ProcessId;
@@ -73,3 +74,45 @@ fn network_policy_request_uses_stable_json_shapes() {
         );
     }
 }
+
+#[test]
+fn network_policy_decision_notification_uses_stable_json_shape() {
+    let notification = NetworkPolicyDecisionNotification {
+        process_id: ProcessId::from("process-1"),
+        timestamp: "2026-08-11T12:34:56.789Z".to_string(),
+        scope: "domain".to_string(),
+        decision: "deny".to_string(),
+        source: "baseline_policy".to_string(),
+        reason: "not_allowed".to_string(),
+        protocol: ExecServerNetworkProtocol::HttpsConnect,
+        host: "example.com".to_string(),
+        port: 443,
+        method: Some("CONNECT".to_string()),
+        client: Some("127.0.0.1".to_string()),
+        policy_override: false,
+    };
+    let expected = serde_json::json!({
+        "processId": "process-1",
+        "timestamp": "2026-08-11T12:34:56.789Z",
+        "scope": "domain",
+        "decision": "deny",
+        "source": "baseline_policy",
+        "reason": "not_allowed",
+        "protocol": "https_connect",
+        "host": "example.com",
+        "port": 443,
+        "method": "CONNECT",
+        "client": "127.0.0.1",
+        "policyOverride": false,
+    });
+
+    assert_eq!(
+        serde_json::to_value(&notification).expect("serialize policy decision notification"),
+        expected
+    );
+    assert_eq!(
+        serde_json::from_value::<NetworkPolicyDecisionNotification>(expected)
+            .expect("deserialize policy decision notification"),
+        notification
+    );
+}