Prompt to unarchive sessions before resuming or forking (#39640)

## Why

Starting an archived session with `codex resume` or `codex fork` stopped with
guidance to run a separate `codex unarchive` command first.

## What changed

- Detect archived-session startup failures and offer to unarchive and retry the
  requested operation.
- Allow the user to cancel without modifying the archived session.
- Render the confirmation in the alternate screen when available and preserve
  inline terminal context when `--no-alt-screen` is set.
- Preserve `--no-alt-screen` whether it appears before or after the `resume` or
  `fork` subcommand.

## Testing

- Cover confirmation, cancellation, retry behavior, and unrelated startup
  failures for both resume and fork.
- Add prompt interaction and terminal rendering coverage, including narrow and
  inline viewports.

GitOrigin-RevId: 382cdbd15b5d12c091e554d6d3a2f9b3589654f4

codex-rs/cli/src/main.rs

@@ -2795,6 +2795,7 @@ fn merge_interactive_cli_flags(interactive: &mut TuiCli, subcommand_cli: TuiCli)
         strict_config,
         approval_policy,
         web_search,
+        no_alt_screen,
         prompt,
         mut config_overrides,
         ..
@@ -2814,6 +2815,7 @@ fn merge_interactive_cli_flags(interactive: &mut TuiCli, subcommand_cli: TuiCli)
     if web_search {
         interactive.web_search = true;
     }
+    interactive.no_alt_screen |= no_alt_screen;
     if strict_config {
         interactive.strict_config = true;
     }
@@ -3772,6 +3774,18 @@ mod tests {
         assert_eq!(interactive.resume_session_id, None);
     }
 
+    #[test]
+    fn resume_and_fork_preserve_no_alt_screen() {
+        for (command, finalize) in [
+            ("resume", finalize_resume_from_args as fn(&[&str]) -> TuiCli),
+            ("fork", finalize_fork_from_args as fn(&[&str]) -> TuiCli),
+        ] {
+            assert!(finalize(&["codex", command, "--no-alt-screen"]).no_alt_screen);
+            assert!(finalize(&["codex", "--no-alt-screen", command]).no_alt_screen);
+            assert!(!finalize(&["codex", command]).no_alt_screen);
+        }
+    }
+
     #[test]
     fn resume_picker_logic_none_and_not_last() {
         let interactive = finalize_resume_from_args(["codex", "resume"].as_ref());