Improve paginated TUI history loading (#36949)

## Why

Paginated sessions can have visible messages beyond the first item page, so
bounded hydration could leave resumed history or transcript previews empty and
the transcript viewer incomplete.

## What changed

- Scan paginated history until the configured rendered-row budget is filled,
  while retaining the configured scrollback beyond the visible viewport.
- Fully hydrate transcripts opened from the resume picker and build previews
  from bounded item pages, including when non-visible items precede messages.
- Stop pagination on repeated cursors and let `Esc` cancel an in-flight
  transcript load.
- Replay restored token usage for cold metadata-only resumes when its stored
  turn can be identified.

## Testing

- Add coverage for paginated and legacy transcript loading, bounded resume
  hydration, repeated cursors, transcript cancellation, and resize reflow.

GitOrigin-RevId: 2ce69f7d5eae88e2b09a27c333b00b1830ff17bf

codex-rs/tui/src/app_server_session.rs

@@ -7,6 +7,9 @@ mod fs;
 mod history;
 
 pub(crate) use history::HISTORY_ITEM_PAGE_LIMIT;
+pub(crate) use history::HISTORY_ITEM_SCAN_LIMIT;
+pub(crate) use history::HistoryHydrationScope;
+pub(crate) use history::thread_items_page_params;
 
 use crate::bottom_pane::FeedbackAudience;
 use crate::legacy_core::config::Config;
@@ -578,6 +581,7 @@ impl AppServerSession {
             response.turns_backwards_cursor.clone(),
             response.items_backwards_cursor.clone(),
             Some(&config),
+            HistoryHydrationScope::Initial,
         )
         .await?;
         let fork_parent_title = self
@@ -691,6 +695,7 @@ impl AppServerSession {
                 /*turn_cursor*/ None,
                 /*item_cursor*/ None,
                 Some(&config),
+                HistoryHydrationScope::Initial,
             )
             .await?;
         }
@@ -824,6 +829,7 @@ impl AppServerSession {
             /*turn_cursor*/ None,
             /*item_cursor*/ None,
             /*config*/ None,
+            HistoryHydrationScope::Initial,
         )
         .await?;
         Ok(response.thread)