Add test-utils.tsx with renderWithProviders (MemoryRouter + I18n + Toast),
mockFetch, and mockFetchRoutes helpers. Create 39 interaction-level tests
across 6 page components covering rendering, form validation, API calls,
delete confirmation flows, SSE progress, and file import/export.
Also add Blob.text() polyfill in test setup for jsdom compatibility.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
oabrivard