Korean input broken in Claude Code CLI on iOS/iPadOS - displays separated jamo

### Checklist
- [x] Using latest version on the [[App Store](http://itunes.apple.com/app/id1156707581)](http://itunes.apple.com/app/id1156707581)
- [x] Read the [[docs](http://blink.sh/docs/)](http://blink.sh/docs/)
- [x] Searched for [[existing GitHub issues](https://github.com/blinksh/blink/issues)](https://github.com/blinksh/blink/issues)

### Configuration
- Blink version: v18.3.0
- iOS/iPadOS version: iPadOS 18.4, iOS 18.5
- Device: iPad and iPhone
- Remote server: Ubuntu 24.04 (via SSH)
- Claude Code CLI version: v1.0.11
- Korean keyboards tested: iOS touch keyboard, iPadOS touch keyboard, Magic Keyboard (hardware)

### Describe the bug
When typing Korean in Claude Code CLI (and other similar AI CLI tools like Codex-cli) through Blink Shell on iOS/iPadOS, Korean characters are displayed broken with separated jamo (individual Korean letters).

**Current behavior:**
- When typing "안녕하세요", it displays as "ㅇ아ㄴ녀ㅇ하ㅅ세ㅇ요" (with separated jamo characters)
- The issue only occurs in REPL environments like Claude Code CLI
- Korean input works perfectly fine in regular SSH sessions, tmux, and Python REPL
- Issue occurs with both software keyboards and hardware Magic Keyboard on iPadOS

**Expected behavior:**
Korean characters should be displayed as complete syllables (e.g., "안녕하세요") without showing intermediate jamo states.

**Screenshots:**

https://github.com/user-attachments/assets/2960ec9b-f373-42ed-b8b3-45edc6bb539f

**Analysis from investigation:**
The issue appears to be caused by:
1. iOS/iPadOS Korean IME sends both intermediate jamo and completed syllable with backspace (0x08)
2. Blink passes these raw bytes unchanged through SSH
3. Claude Code's Ink-based TUI doesn't properly handle the 0x08 backspace, leaving both jamo and syllable on screen

**Additional information:**
- The same issue occurs with Termius on iOS
- Works correctly on iTerm2 and Linux terminals
- Only affects REPL environments using Ink-based TUI, not regular shell sessions

**Steps to reproduce:**
1. Connect to Ubuntu 24.04 server via SSH using Blink on iPad/iPhone
2. Launch Claude Code CLI (`claude`)
3. Try typing Korean text (e.g., "안녕하세요")
4. Observe that jamo characters remain visible alongside completed syllables

**Potential solutions: (not by me, suggested by AI) **
- Terminal-side: Filter out intermediate jamo/0x08 sequences before sending to REPL
- CLI-side: Proper handling of CJK IME composition in Ink-based TUI
- Workaround: Use terminals that handle IME composition differently (e.g., iTerm2 on macOS)

Reproduce the issue by connecting to Ubuntu 24.04 over SSH from Blink and launching the Claude Code CLI with `claude`; compare Korean input in regular SSH, tmux, and Python REPL sessions. Trace whether iOS/iPadOS IME bytes, including 0x08, are passed unchanged, then verify that completed Korean syllables render correctly in the REPL.

Written by the indexing model from the issue text.