[Bug] Fullscreen TUI: Cmd+Left/Right still broken in Warp (re #50503)

Following up on #50503, which was closed as fixed in 2.1.116 and then auto-locked. The locked issue's auto-comment instructs to file a fresh issue and reference the original, so here it is.

The bug still reproduces for me on the latest Claude Code release - I believe the cause is terminal-specific: I'm running Claude Code inside Warp.app, and the fix that landed in 2.1.116 may not cover Warp's keybinding layer.

Environment

• Claude Code: 2.1.140
• Platform: macOS (Darwin 25.3.0)
• Shell: zsh
• Terminal: Warp.app (latest stable)
• TUI mode: /tui fullscreen

Summary

In fullscreen TUI mode, Cmd+Left / Cmd+Right still do not move the cursor to the beginning / end of the current line in the prompt input. This matches the original symptom described in #50503.

Steps to reproduce

1. Open Warp.app.
2. Launch Claude Code (claude) and run /tui fullscreen.
3. Type a multi-word prompt into the input, e.g. hello world this is a test.
4. Place the cursor somewhere in the middle of the text.
5. Press Cmd+Left (expected: cursor jumps to start of line).
6. Press Cmd+Right (expected: cursor jumps to end of line).

Expected

• Cmd+Left -> cursor moves to the beginning of the current line.
• Cmd+Right -> cursor moves to the end of the current line.

Matches default macOS text-editing behavior and works in the non-fullscreen TUI mode.

Actual

• Cmd+Left / Cmd+Right are not handled - the cursor stays where it is (or the keypress is swallowed). Same symptom as #50503.

Notes

• Non-fullscreen TUI mode behaves correctly even in Warp - the issue is specific to /tui fullscreen.
• Other macOS-standard editing shortcuts (Cmd+Backspace, Option+Left/Right) - please confirm separately if you'd like; I can add details on those in a comment if helpful.
• It's possible Warp intercepts/transforms Cmd+Left/Right at the terminal-emulator layer before it reaches the TUI; if so, this would be worth documenting (or worth detecting and showing a hint).

Related: #50503 (closed/locked).