fix: use runtime fallback for zoxide cd function

[ki11e6]

Summary

• Removes alias cd='z' from defaults/bash/aliases
• Adds a cd() function in defaults/bash/init with runtime fallback to builtin cd

Problem

The cd command fails with bash: command not found: __zoxide_z in non-interactive shell environments (e.g., Claude Code CLI, scripts, CI/CD pipelines).

Root cause: Zoxide's __zoxide_z function is not available in non-interactive shells because eval "$(zoxide init bash)" doesn't properly define functions in these contexts. See: anthropics/claude-code#2407

Previous Fix Attempt (didn't fully work)

# Source-time check - only creates alias if function exists at source time
if declare -f __zoxide_z &> /dev/null; then
  alias cd='z'
fi

Why it failed: This checks only once when the file is sourced. In some environments, the shell state can become inconsistent (functions defined but later unavailable), or tools like mise can override the cd function after our alias is set.

New Fix (runtime fallback)

cd() {
  if declare -f __zoxide_z &>/dev/null; then
    __zoxide_z "$@"
  else
    builtin cd "$@"
  fi
}

Why this works:

1. Checks at execution time whether __zoxide_z is available
2. Uses zoxide when available (interactive shells)
3. Falls back gracefully to builtin cd when not (non-interactive shells)
4. Never produces errors in any environment

Test Results

Environment	cd behavior	Result
Interactive shell	Uses __zoxide_z	✅ zoxide works
Non-interactive shell	Falls back to builtin cd	✅ no errors
Claude Code CLI	Falls back to builtin cd	✅ no errors

Test plan

• Verified cd uses zoxide in interactive shells
• Verified cd falls back to builtin in non-interactive shells
• Verified no __zoxide_z errors in any environment
• Verified .., ... aliases still work in interactive shells

[Kasui92]

I think it's more correct to separate init from aliases.
In this #562 I'm introducing the same configuration that was used on Omarchy, which solves this problem.

if command -v zoxide &> /dev/null; then
  alias cd="zd"
  zd() {
    if [ $# -eq 0 ]; then
      builtin cd ~ && return
    elif [ -d "$1" ]; then
      builtin cd "$1"
    else
      z "$@" && printf "\U000F17A9 " && pwd || echo "Error: Directory not found"
    fi
  }
fi

[ki11e6]

Thanks for the feedback @Kasui92! Your approach from Omarchy is actually much better.

Happy to defer to PR #562 if it's addressing this more comprehensively. Should I close this PR in favor of that one?

[Kasui92]

I think so, that might be enough, even just to have a similar alignment with what's being done on Omarchy.