[codex] abort turns when rollout budgets expire (token budget 3/3) (#28707)

## Stack

Depends on #28494.

## Description

This PR propagates shared rollout-budget exhaustion through the existing
`CodexErr::TurnAborted` task result.

Each thread records its model usage against the same ledger. Once the
ledger is exhausted, that usage update and all later usage updates
return `TurnAborted`. The task wrapper emits the normal aborted-turn
event and lifecycle instead of completing the turn.

This is intentionally a soft boundary: there is no cross-thread
`Op::Interrupt` fanout. An in-flight thread can finish its current
response before it observes the exhausted ledger, but every thread
aborts at its next usage-accounting boundary.

## Tests

The integration coverage verifies that:

- the response that exhausts the budget aborts its turn;
- a later response also aborts because the shared ledger remains
exhausted; and
- sub-agent usage draws from the same shared ledger; and
- local and remote-v2 compaction abort without retrying or emitting a
generic error.

Local checks:

- `just test -p codex-core
exhausted_budget_aborts_current_and_later_turns`
- `just test -p codex-core subagent_usage_draws_from_the_shared_budget`
- `just test -p codex-core
abort_regular_task_emits_marker_before_turn_aborted`
- `just test -p codex-core
compaction_budget_exhaustion_aborts_without_error_or_retry`
- `just fix -p codex-core`
- `just fmt`
- `git diff --check`

The full workspace test suite was not run locally.

codex-rs/core/src/compact_remote_v2.rs

@@ -165,6 +165,9 @@ async fn run_remote_compact_task_inner(
     attempt
         .track(sess.as_ref(), status, codex_error, analytics_details)
         .await;
+    if matches!(&result, Err(CodexErr::TurnAborted)) {
+        return result;
+    }
     if let Err(err) = result {
         sess.track_turn_codex_error(turn_context, &err);
         let event = EventMsg::Error(
@@ -281,7 +284,7 @@ async fn run_remote_compact_task_inner_impl(
         token_usage,
     } = compaction_output_result?;
     if let Some(token_usage) = token_usage {
-        sess.record_rollout_budget_usage(&token_usage);
+        sess.record_rollout_budget_usage(&token_usage)?;
         analytics_details.active_context_tokens_before = Some(token_usage.input_tokens);
         analytics_details.compaction_summary_tokens = Some(token_usage.output_tokens);
         analytics_details.cached_input_tokens = Some(token_usage.cached_input_tokens);