[codex] surface rollout budget exhaustion (#29715)

## Summary
- surface shared rollout-budget exhaustion as
`CodexErr::RolloutBudgetExceeded` instead of a generic interrupted turn
- map it through the existing `CodexErrorInfo` and app-server v2
`codexErrorInfo` path
- keep local compaction from retrying after the shared rollout budget is
exhausted

This gives app-server clients a stable `rolloutBudgetExceeded` error
they can classify without guessing from `status="interrupted"`.

## Tests
- `just test -p codex-core rollout_budget`

codex-rs/core/src/compact.rs

@@ -275,6 +275,12 @@ async fn run_compact_task_inner_impl(
             Err(err @ (CodexErr::Interrupted | CodexErr::TurnAborted)) => {
                 return Err(err);
             }
+            Err(e @ CodexErr::RolloutBudgetExceeded) => {
+                sess.track_turn_codex_error(turn_context.as_ref(), &e);
+                let event = EventMsg::Error(e.to_error_event(/*message_prefix*/ None));
+                sess.send_event(&turn_context, event).await;
+                return Err(e);
+            }
             Err(e @ CodexErr::ContextWindowExceeded) => {
                 if turn_input_len > 1 {
                     // Trim from the beginning to preserve cache (prefix-based) and keep recent messages intact.

codex-rs/core/src/session/rollout_budget.rs

@@ -30,7 +30,7 @@ impl Session {
             .rollout_budget()
             .record_usage(usage)
         {
-            return Err(CodexErr::TurnAborted);
+            return Err(CodexErr::RolloutBudgetExceeded);
         }
         Ok(())
     }