Improve Deployer command error messages

[lang315]

Fixes #4

Summary

• include the full Deployer command in failure messages
• preserve stderr/stdout or the original error so missing binaries are visible
• add a targeted hint for missing PHP or Deployer binaries
• rebuild dist/index.js

Verification

• npm run typecheck
• npm run format:check
• npm run build
• env INPUT_SKIP-SSH-SETUP=true INPUT_DEP=list INPUT_DEPLOYER-BINARY=package.json INPUT_PHP-BINARY=/tmp/deployphp-action-missing-php INPUT_ANSI=false INPUT_VERBOSITY= node dist/index.js