[Bug] Astra composer sparkle animation prevents mouse text selection in kitty (0.154.0)

Environment

• Codex CLI: 0.154.0
• OS: macOS 26.6.2
• Terminal: kitty 0.48.2
• Model: GPT-6-Astra

Steps to reproduce

1. Start Codex with the default decorative animations enabled.
2. Select GPT-6-Astra.
3. Enter text in the input composer.
4. Try selecting the text by dragging with the mouse.

Actual behavior

Text cannot be selected while the sparkle animation is active, preventing copying from the composer. The failure happens at the selection step, before invoking a copy command.

Switching to another model removes the animation and restores selection. Switching back to Astra reproduces the problem.

Expected behavior

Decorative animations should not interfere with native terminal text selection or copying.

Verified workaround

Add the following setting to ~/.codex/config.toml and restart Codex:

[tui]
whimsy = false

I confirmed that text selection works again with Astra still selected after disabling this effect and restarting Codex.

Possible investigation lead

In version 0.154.0, chat_composer/sparkle.rs schedules animation frames every 150 ms. These redraws may interfere with kitty's selection handling; this is a hypothesis, not a confirmed root cause.

Start in codex-rs/tui/src/bottom_pane/chat_composer/sparkle.rs, where the Astra sparkle animation schedules frames every 150 ms. Reproduce the issue in kitty 0.48.2 with Codex CLI 0.154.0, then investigate whether those redraws disrupt native mouse selection in the composer. Done means text remains selectable and copyable with Astra and decorative animations enabled.