feat(core): persist network approvals in execpolicy (#12357)

## Summary
Persist network approval allow/deny decisions as `network_rule(...)`
entries in execpolicy (not proxy config)

It adds `network_rule` parsing + append support in `codex-execpolicy`,
including `decision="prompt"` (parse-only; not compiled into proxy
allow/deny lists)
- compile execpolicy network rules into proxy allow/deny lists and
update the live proxy state on approval
- preserve requirements execpolicy `network_rule(...)` entries when
merging with file-based execpolicy
- reject broad wildcard hosts (for example `*`) for persisted
`network_rule(...)`

codex-rs/protocol/src/protocol.rs

@@ -57,6 +57,8 @@ pub use crate::approvals::ExecApprovalRequestEvent;
 pub use crate::approvals::ExecPolicyAmendment;
 pub use crate::approvals::NetworkApprovalContext;
 pub use crate::approvals::NetworkApprovalProtocol;
+pub use crate::approvals::NetworkPolicyAmendment;
+pub use crate::approvals::NetworkPolicyRuleAction;
 pub use crate::request_user_input::RequestUserInputEvent;
 
 /// Open/close tags for special user-input blocks. Used across crates to avoid
@@ -2756,6 +2758,12 @@ pub enum ReviewDecision {
     /// remainder of the session.
     ApprovedForSession,
 
+    /// User chose to persist a network policy rule (allow/deny) for future
+    /// requests to the same host.
+    NetworkPolicyAmendment {
+        network_policy_amendment: NetworkPolicyAmendment,
+    },
+
     /// User has denied this command and the agent should not execute it, but
     /// it should continue the session and try something else.
     #[default]
@@ -2774,6 +2782,12 @@ impl ReviewDecision {
             ReviewDecision::Approved => "approved",
             ReviewDecision::ApprovedExecpolicyAmendment { .. } => "approved_with_amendment",
             ReviewDecision::ApprovedForSession => "approved_for_session",
+            ReviewDecision::NetworkPolicyAmendment {
+                network_policy_amendment,
+            } => match network_policy_amendment.action {
+                NetworkPolicyRuleAction::Allow => "approved_with_network_policy_allow",
+                NetworkPolicyRuleAction::Deny => "denied_with_network_policy_deny",
+            },
             ReviewDecision::Denied => "denied",
             ReviewDecision::Abort => "abort",
         }