Fix Android IME rollover and stabilize deferred theme E2E

[bifrost0x]

Summary

• wait for the deferred auth-theme background readiness signal before inspecting computed styles
• preserve the intentional idle-time background loading behavior
• handle Android IME input-before-keydown rollover without replaying text through xterm
• keep normal composition, Backspace, modified shortcuts, and screen-reader input on their existing paths

Root causes

Deferred theme assertion

The test waited for the stored paper theme but immediately inspected the deferred background image. On a busy runner, requestIdleCallback had not yet added data-theme-background-ready, so the assertion saw the intended temporary none value. The failure trace showed the background request succeeding immediately after the assertion failed.

Android IME rollover

Some Android IMEs can emit an insertText input event before a keydown with key code 229 and without composition events. xterm then schedules its own textarea-diff fallback and can replay stale text, producing duplicated or truncated terminal input. The guard now observes that ordering before xterm capture handling and suppresses only the paired fallback keydown.

Testing

• all JavaScript tests: 40 passed
• complete theme-system.spec.js: 6 passed
• Android composition and input-before-keydown browser regressions: 2 passed
• terminal selection and 360px mobile workspace browser regressions: 2 passed
• ESLint on all changed JavaScript and E2E files
• git diff --check

Validation boundary

The Android regression is covered through the real xterm browser integration in Chromium. It has not yet been verified on a physical OnePlus Pad 3 running Android 16 and Brave.

Failure reference: https://github.com/bifrost0x/webssh/actions/runs/34197698324

Fixes #210

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-08T07:23:36.839091Z	d81a071	PR opened

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