Catch broken component exports before they ship

When a shared UI package declares an export that points at a missing file, the apps that use it break, and people start importing internal files instead. This check reads a package's declared exports and confirms each one resolves to a file inside the package.

Run it after a build, when the local export targets should exist. It covers the package side of shared components: the exports are present and real. It checks files, not how components look; compare spacing and states in a state gallery and in the real consumers.

It runs locally from the command line with Python 3.10 or later, on Windows, macOS and Linux. Provider accounts, model weights, GPU compute and hosting are not included.