Add LLM hooks management support

[mrexox]

Description

Claude and Codex have hooks, and managing them through lefthook feels like something useful.

What problem it is solving?

You don't need to define hooks for the Claude, Codex, etc. You add a hook to lefthook.yml and generate the configs for the provider of your choice.

Details

Need to think of the better approach and configuration option.

Option 1 – Strictly configurable

# lefthook.yml

ai:
  claude:
    Stop: validate # references a named lefthook hook

validate:
  jobs:
    - run: go test ./...

Merges to:

// .claude/settings.json

{
  ... // other local user settings
  "hooks": {
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "lefthook run validate"
          }
        ]
      }
    ]
  }
} 

Option 2 – Ask user

Stop:
  jobs:
    - run: go test ./...

When you run lefthook install

1. Detects you have configured hooks for LLM (by name)
2. Asks if you prefer to use Claude or Codex
   2.1. Another option is to check existing .claude/ and .codex/ dirs
3. Installs the hook (which call lefthook run Stop)