feat(mobile): add compact terminal key layouts

[KoenLemmen]

What changed

Replace the mobile terminal's horizontal key scroller with a compact, two-row grid. FN switches between the default, function-key, and navigation layouts.

Existing key handlers, modifier state, keyboard control, and terminal theme colors remain unchanged.

Why

The current toolbar splits common keys across scroll positions. The fixed grid keeps common controls and the arrow cluster visible, gives each key a stable position, and adds function and navigation keys while increasing the accessory height by 18 points.

UI changes

Before	Before, scrolled

Default	Function keys	Navigation keys

Watch the dark-mode FN interaction (11 seconds)

Validation

• vp run --filter @t3tools/mobile typecheck
• Targeted lint, formatting, and git diff --check
• Pixel 6 emulator on Android 15
• Verified all layouts, modifiers, paste, keyboard control, and terminal theme colors

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots
• I included an interaction video

Model: GPT-5.6 Sol. Harness: Codex in T3 Code.

Summary by CodeRabbit

• New Features

  • Rebuilt the terminal keyboard accessory as a fixed two-row keypad for easier access.
  • Added main, function, and navigation modes with an “fn” button for switching layouts.
  • Added visual states for active modifiers, icons, labels, and key dividers.

• Improvements

  • Expanded the accessory height to provide a more spacious terminal control layout.

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ℹ️ Recent review info

⚙️ Run configuration

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📥 Commits

Reviewing files that changed from the base of the PR and between 371b52d and f37e753.

📒 Files selected for processing (1)

• apps/mobile/src/features/terminal/ThreadTerminalRouteScreen.tsx

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📝 Walkthrough

Walkthrough

The terminal keyboard accessory changes from one horizontally scrolling toolbar row to a fixed two-row keypad. Three modes provide main, function, and navigation keys. The accessory height increases to 70 pixels, and an fn button cycles modes.

Changes

Terminal keypad

Layer / File(s)	Summary
Define keypad layouts and buttons apps/mobile/src/features/terminal/ThreadTerminalRouteScreen.tsx	The screen adds three toolbar modes, fixed seven-action rows, ANSI key sequences, platform theme typing, and a themed TerminalAccessoryButton.
Integrate mode state and rendering apps/mobile/src/features/terminal/ThreadTerminalRouteScreen.tsx	The screen stores the active mode, builds platform-specific layouts, increases the accessory height from 52 to 70, and renders two fixed rows with fn and dismiss controls.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Feature

Suggested reviewers: juliusmarminge

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: adding compact terminal key layouts for mobile.
Description check	✅ Passed	The description explains what changed, why it changed, and the UI impact. It includes before/after screenshots, an interaction video, validation details, and a completed checklist.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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🧪 Generate unit tests (beta)

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