Vitest test authoring

Read applicable AGENTS.md and their declared adapter alias, otherwise .agents/skills/vitest-test-authoring/SKILL.md from the repository root if present. Local policy overrides these defaults; do not reload an already-read adapter or canonical skill.

Apply test-authoring first.

• Isolate tests with Vitest lifecycle hooks. Restore spies and globals after each test.
• Prefer a deterministic async assertion over a timing wait.
• Mock an external boundary. Do not mock the module under test.
• Use a typed factory when the project supplies one.
• Run the selected file or project before broader validation.
• Read mock boundaries when adding a module mock or changing an export.

Consumer wrapper owns: project selection, mock boundaries, fixture names, and coverage policy.