[BUG] Installation corrupts alacritty.toml when `keyboard.bindings` is already defined as an inline array

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code installation appends a keybinding to ~/.config/alacritty/alacritty.toml using the TOML array of tables syntax ([[keyboard.bindings]]). If the config file already defines keyboard.bindings as an inline array, TOML considers this a duplicate key and refuses to parse the file. As a result, Alacritty fails to start after installing Claude Code.

The installer added:

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

But the existing config already had:

[keyboard]
bindings = [
  { key = "M", mods = "Control", action = "None" },
  { key = "Y", mods = "Control", action = "None" },
]

These two syntaxes are incompatible in TOML — mixing an inline array with [[...]] array-of-tables for the same key is not allowed.

What Should Happen?

The installer should detect the existing keyboard.bindings definition and merge the new binding into it, rather than blindly appending a [[keyboard.bindings]] block. The result should look like:

[keyboard]
bindings = [
  { key = "M", mods = "Control", action = "None" },
  { key = "Y", mods = "Control", action = "None" },
  { key = "Return", mods = "Shift", chars = "\^[\r" },
]

Error Messages/Logs

[ERROR] Unable to load config "/home/user/.config/alacritty/alacritty.toml": Config error: TOML parse error at line 115, column 1
  |
115 | [[keyboard.bindings]]
  | ^
invalid table header
duplicate key `bindings` in table `keyboard`

See log at /tmp/Alacritty-35421.log ($ALACRITTY_LOG)

Steps to Reproduce

1. Have an existing ~/.config/alacritty/alacritty.toml with a [keyboard] section using inline array syntax for bindings
2. Install Claude Code
3. Open Alacritty — it fails with the duplicate key error above

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.80 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_