Fixes (#4458)

Fixing the "? for shortcuts"

- Only show the hint when composer is empty
- Don't reset footer on new task updates
- Reorder the elements
- Align the "?" and "/" with overlay on and off

Based on #4364

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__chatwidget_exec_and_status_layout_vt100_snapshot.snap

@@ -13,6 +13,3 @@ expression: term.backend().vt100().screen().contents()
 
 
 › Summarize recent commits
-
-
-  ? for shortcuts

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__status_widget_active.snap

@@ -1,5 +1,6 @@
 ---
 source: tui/src/chatwidget/tests.rs
+assertion_line: 1445
 expression: terminal.backend()
 ---
 "                                                                                "
@@ -8,6 +9,5 @@ expression: terminal.backend()
 "                                                                                "
 "› Ask Codex to do anything                                                      "
 "                                                                                "
-"                                                                                "
 "  ? for shortcuts                                                               "
 "                                                                                "