Batch persistent history reads during reverse search (#33905)

## Why

Reverse search fetched persistent history one entry at a time, making a deep or unsuccessful search require a lookup for every older entry.

## What changed

- Keep the newest-entry probe lightweight, then scan older persistent history in bounded batches.
- Cache batch results by absolute offset and preserve continuation cursors across repeated searches.
- Ignore stale responses, retry failed batch reads a bounded number of times, and restore the draft without reporting a false “no match” state when history is unavailable.

## Testing

- Cover batch continuation, caching after query changes or cancellation, stale metadata, retry exhaustion, and thread routing.
- Verify that scanning 1,024 entries uses one single-entry lookup and eight batch lookups.

GitOrigin-RevId: efc791fcbd5290050af703dd31c5c21b33240e23

codex-rs/tui/src/app_event.rs

@@ -32,6 +32,7 @@ use codex_app_server_protocol::SkillsListResponse;
 use codex_app_server_protocol::ThreadGoalStatus;
 use codex_connectors::AppInfo;
 use codex_file_search::FileMatch;
+use codex_message_history::HistoryBatchCursor;
 use codex_protocol::ThreadId;
 use codex_protocol::openai_models::ModelPreset;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -65,13 +66,39 @@ pub(crate) enum ThreadGoalSetMode {
     },
 }
 
-#[derive(Debug, Clone)]
-pub(crate) struct HistoryLookupResponse {
+/// One absolute history offset returned by a batch lookup.
+///
+/// Malformed rows retain their offset with `entry` set to `None` so the composer can cache the gap
+/// without shifting every older record.
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) struct HistoryBatchEntryResponse {
     pub(crate) offset: usize,
-    pub(crate) log_id: u64,
     pub(crate) entry: Option<String>,
 }
 
+/// Persistent-history data routed back to the thread that requested it.
+///
+/// Batch responses preserve absolute offsets and malformed-row gaps so the composer can cache the
+/// data independently of whichever search query is active when the response arrives.
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) enum HistoryLookupResponse {
+    Entry {
+        offset: usize,
+        log_id: u64,
+        entry: Option<String>,
+    },
+    Batch {
+        cursor: HistoryBatchCursor,
+        log_id: u64,
+        entries: Vec<HistoryBatchEntryResponse>,
+        next_older_cursor: Option<HistoryBatchCursor>,
+    },
+    BatchError {
+        cursor: HistoryBatchCursor,
+        log_id: u64,
+    },
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) enum ConsolidationScrollbackReflow {
     IfResizeReflowRan,
@@ -200,6 +227,13 @@ pub(crate) enum AppEvent {
         log_id: u64,
     },
 
+    /// Fetch a bounded batch of persistent history entries for reverse search.
+    LookupMessageHistoryBatch {
+        thread_id: ThreadId,
+        cursor: HistoryBatchCursor,
+        log_id: u64,
+    },
+
     /// Start a new session.
     NewSession,