Vitest 4 silently ignores per-project coverage overrides in test.projects,
so a standalone vitest.client-coverage.config.ts provides the root-level
Istanbul coverage block that Vitest actually honours.
Root vite.config.ts retains the v8 coverage block (reportsDirectory:
coverage/server) for the server project. The client config writes to
coverage/client and instruments all .svelte and .svelte.ts files.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
