Install multiple global versions with pipx

## Goal
Install upstream and forked CLI variants globally using `pipx`.

## Commands
```bash
brew install pipx
pipx ensurepath

pipx install claude-code-transcripts
pipx install --force --suffix="-fork" .
```

## Expected Binaries
- `claude-code-transcripts`
- `claude-code-transcripts-fork`

## Acceptance Criteria
- Both binaries available on PATH
- `--help` works for both
