fix(runner): retain Codex sessions across late usage snapshots

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/paperclip-runner/runner/crates/runner-core/src/bin/fake-codex-app-server.rs

@@ -1632,6 +1632,12 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                     }
                     if emit_post_completion_passive_statuses {
                         for notification in [
+                            json!({
+                                "method": "thread/tokenUsage/updated",
+                                "params": {"threadId": state.thread_id, "turnId": provider_turn_id,
+                                    "tokenUsage": {"total": {"inputTokens": 120, "outputTokens": 12},
+                                        "last": {"inputTokens": 20, "outputTokens": 2}}}
+                            }),
                             json!({
                                 "method": "remoteControl/status/changed",
                                 "params": {"status": "disabled", "environmentId": null}

packages/paperclip-runner/runner/crates/runner-core/src/codex_provider.rs

@@ -1260,6 +1260,9 @@ impl CodexProvider {
                             | "thread/goal/updated"
                             | "thread/goal/cleared"
                             | "thread/tokenUsage/updated"
+                            // poll() normalizes usage from this settled turn.
+                            // It remains an accounting snapshot, not new work.
+                            | "paperclip/resumeUsageSnapshot"
                             | "thread/status/changed"
                             | "turn/diff/updated"
                             | "turn/plan/updated"
@@ -3988,6 +3991,31 @@ done
         provider
     }
 
+    #[cfg(unix)]
+    #[test]
+    fn warm_attachment_accepts_normalized_usage_for_the_completed_turn() {
+        let mut provider = completion_tail_provider();
+        provider
+            .restore_completed_turn_authority(true, Some(1), Some("reader-tail-1"))
+            .unwrap();
+        provider.active_provider_turn_id = None;
+        provider
+            .pending_messages
+            .push_back(BufferedProviderMessage {
+                value: json!({
+                    "method": "thread/tokenUsage/updated",
+                    "params": {"threadId": "reader-tail-thread", "turnId": "reader-tail-1",
+                        "tokenUsage": {"total": {"inputTokens": 120, "outputTokens": 12}}}
+                }),
+                trace_frame_id: None,
+            });
+        // poll() normalizes settled-turn usage to paperclip/resumeUsageSnapshot.
+        // That accounting fact is not new work and must not force replacement.
+        let result = provider.drain_completed_turn_tail_for_warm_attachment();
+        provider.shutdown().unwrap();
+        result.expect("historical usage must not break provider continuity");
+    }
+
     #[cfg(unix)]
     struct HeldTerminalReader {
         release: Option<mpsc::Sender<()>>,

packages/paperclip-runner/runner/crates/runner-core/tests/codex_provider.rs

@@ -3521,7 +3521,7 @@ fn durable_backend_rotates_tool_authority_for_fresh_run_attach() {
 }
 
 #[test]
-fn durable_backend_drains_a_bounded_completed_turn_tail_during_warm_attach() {
+fn durable_backend_drains_completed_turn_usage_and_passive_tail_during_warm_attach() {
     let directory = temporary_directory("durable-warm-attach-tail");
     let config = provider_config(
         &directory,