Update all Make targets, comments, docs, and scripts to use the plural
form, reflecting that APPS can specify more than one application.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Makes clear that multiple space- or comma-separated app ids are
supported. Renames the env var, CLI flag (--app → --apps), and all
references in scripts, workflows, and documentation.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>