Stryker counts a static mutant that breaks a module's import as survived #851

What happens

Stryker's vitest runner reports a static mutant that makes a module throw on import as survived. The runner keeps only the tests it collected, and a test file that fails to import collects none, so the mutant looks alive.

Seen while re-running the tool-profile scopes for #837 (PR #844): mutants such as DIRECTORY → "" or new SkillsCapability({}) are reported as survived. The same mutant applied by hand fails cursor.unit.test.ts outright, with SkillsCapability requires either prefix or directory. Five such survivors remain across tools-claude, tools-cursor and tools-copilot.

Expected

A mutant that stops a module from loading counts as killed. A test file that cannot be imported is a failing test, not an absent one.

Impact

It lowers a score and never inflates one, so no gate passes wrongly. But a scope can sit below the floor its tests deserve, and each false survivor in a report sends someone after a test gap that does not exist.