terminal-setup writes invalid TOML escape sequence for Alacritty config

Description

The /terminal-setup command writes an invalid escape sequence to the Alacritty configuration file, causing a TOML parse error.

Steps to Reproduce

1. Run /terminal-setup in Claude Code with Alacritty as terminal
2. Alacritty fails to load config with error:

```
[ERROR] Unable to load config "~/.config/alacritty/alacritty.toml": Config error: TOML parse error at line 30, column 12

30 | chars = "\x1b\r"

Invalid escape sequence
expected 'b', 'f', 'n', 'r', 't', 'u', 'U', '\', '"'
```

Root Cause

The CLI writes:

[[keyboard.bindings]]
key = "Return"
mods = "Shift"
chars = "\x1b\r"

TOML does not support \x escape sequences. TOML only supports:

• \b, \f, \n, \r, \t (standard escapes)
• \uXXXX and \UXXXXXXXX (Unicode escapes)
• \\ and \" (literal backslash and quote)

Expected Behavior

The config should use the TOML-compatible Unicode escape format:

chars = "\^[\r"

Environment

• Claude Code version: v2.1.12
• Terminal: Alacritty
• OS: macOS