Add v0k fix for repairing failed commands

[Copilot]

Adds a v0k fix entrypoint that accepts failed-command context from shell integration, asks the existing AI healing flow for a correction, and can execute or preview the suggested command.

• CLI

  • Added v0k fix
  • Supports --command, --exit-code, --dry-run, --explain, and --json
  • Prompts when the suggestion is low-confidence or potentially destructive

• Shell integration

  • Shows setup guidance when v0k fix is run without --command
  • Documents optional bash/zsh wrapper:

v0k() {
  local exit_code=$?
  if [ "$1" = "fix" ]; then
    local last_cmd
    last_cmd="$(fc -ln -1)"
    command v0k fix --command "$last_cmd" --exit-code "$exit_code" "${@:2}"
  else
    command v0k "$@"
  fi
}

• Output modes

  • Human-readable fix suggestion by default
  • JSON output for integrations
  • Dry-run mode to preview without execution

• Coverage

  • Added CLI tests for missing shell-context guidance and dry-run JSON suggestions