Simplify queued user message admission (#38092)

## What changed

- Resolve user message admission when Core accepts the input as a new turn or a steer, without waiting for rollout persistence.
- Remove persistence- and hook-specific admission errors and task bookkeeping.
- Delete queued messages after Core accepts them for turn processing, including messages subsequently stopped by a prompt hook.

## Testing

- Update concurrent admission and queue service tests for acceptance-based admission.

GitOrigin-RevId: 7dcc311cfecd3d710733b420f2add546edb86153

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

@@ -18,7 +18,6 @@ use crate::hook_runtime::drain_async_hook_results;
 use crate::hook_runtime::inspect_pending_input;
 use crate::hook_runtime::record_additional_contexts;
 use crate::hook_runtime::record_pending_input;
-use crate::hook_runtime::reject_pending_input;
 use crate::hook_runtime::run_legacy_after_agent_hook;
 use crate::hook_runtime::run_pending_session_start_hooks;
 use crate::hook_runtime::run_turn_stop_hooks;
@@ -603,34 +602,26 @@ pub(crate) async fn run_hooks_and_record_inputs(
 ) -> bool {
     let mut blocked_input = false;
     let mut accepted_user_input = false;
-    let mut persistence_failed = false;
     for input_item in input {
         let hook_outcome = inspect_pending_input(sess, turn_context, input_item).await;
         if hook_outcome.should_stop {
             blocked_input = true;
-            reject_pending_input(sess, turn_context, input_item).await;
             record_additional_contexts(sess, turn_context, hook_outcome.additional_contexts).await;
         } else {
             if matches!(input_item, TurnInput::UserInput { content, .. } if !content.is_empty()) {
                 accepted_user_input = true;
             }
-            if record_pending_input(
+            record_pending_input(
                 sess,
                 turn_context,
                 input_item.clone(),
                 hook_outcome.additional_contexts,
                 persist_context,
             )
-            .await
-            .is_err()
-            {
-                // Preserve later drained inputs, but stop before sampling so a
-                // later queue retry cannot execute this message twice.
-                persistence_failed = true;
-            }
+            .await;
         }
     }
-    persistence_failed || (blocked_input && !accepted_user_input)
+    blocked_input && !accepted_user_input
 }
 
 fn turn_user_input(input: &[TurnInput]) -> Vec<UserInput> {