fix(mobile): Android terminal keystrokes paint immediately

[macodev00]

What Changed

Android terminal keystrokes now paint in the native surface before the remote pty echoes them. Printable input is fed to Ghostty immediately, then reconciled with the authoritative pty byte stream so a matching echo is drawn once. If the pty does not echo those bytes, the grid is rebuilt from the pty buffer and local echo stays off until a later keystroke is echoed verbatim.

Trusted prediction stops at the same pending-input cap as the untrusted probe, and further keystrokes fall back to remote echo. Password, passphrase, passcode, and PIN prompts, including ones with a URL or a parenthetical, are left for the pty. A control key holds local echo until the pty answers, and a rebuild does not resend device replies for history the previous session already answered.

This supersedes pingdotgg#13233 (Macroscope not approved) and pingdotgg#13226. The three blocking findings from pingdotgg#13233 are baked in:

1. Secret-prompt detection inspects the current line after the last newline or carriage return, then strips ANSI. It does not takeLast(240) first, so a long Password for 'https://…': line cannot drop the leading Password token while keeping the trailing colon.
2. Trusted keys refused at the pending-input cap stay in pendingInput. Painting stays off until those bytes are echoed, so a partial echo cannot paint the next key and later reset the grid.
3. awaitingRemote stays set while a new snapshot is only the outstanding printable echo (for example ls after ls + Enter). It clears once CR/LF or other control processing is visible.

Fixes pingdotgg#12756

Supersedes pingdotgg#13233 and pingdotgg#13226

Why

Characters were drawn only after a full attach round trip. On a phone that delay is visible on every key. pingdotgg#13226 was not approved because a trusted session could grow the predicted buffer without limit, and the prompt check missed Passcode: and PIN:. pingdotgg#13233 fixed those, then Macroscope rejected long-prompt detection, cap overflow after a partial echo, and clearing awaitingRemote on a printable-only suffix.

UI Changes

This changes when typed characters appear in the Android terminal. Layout is unchanged. This environment has no Android emulator (/dev/kvm is unavailable) and no device, so there is no before/after recording. Reconciliation is covered by TerminalLocalEchoTest.

iOS still paints from the remote buffer. This report is the Android client.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Screenshots do not show the latency. A recording needs a device build of the native terminal module.

  

[macodev00]

Superseded by upstream READY PR on pingdotgg/t3code (same branch).