Add durable user-message queue dispatch (#37204)

## What changed

- Add a storage-neutral queue extension for listing, adding, editing, reordering, deleting, and explicitly starting queued user messages.
- Dispatch queued messages in FIFO order when a thread becomes idle after a completed turn, while leaving them queued after interruptions or failures.
- Wait for user input to be persisted before removing its queue item, and report hook rejection, task termination, and persistence failures distinctly.
- Snapshot local image and audio attachments into validated data URLs before storing them, enforce input limits, and emit `ThreadQueueChanged` events after mutations.

## Testing

- Cover queue mutations, automatic and explicit dispatch, interruption and failure behavior, hook rejection, invalid records, input limits, and local attachment snapshotting.

GitOrigin-RevId: 14f39d7c8cbaccb767a6da84b82cced0edfcb4b9

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

@@ -4,13 +4,15 @@ use crate::state::TurnState;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::protocol::InterAgentCommunication;
 use codex_protocol::user_input::UserInput;
+use serde::Deserialize;
+use serde::Serialize;
 use std::collections::VecDeque;
 use std::sync::Arc;
 use tokio::sync::Mutex;
 use tokio::sync::watch;
 
 /// Input consumed by a regular turn.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub enum TurnInput {
     UserInput {
         content: Vec<UserInput>,