[unit: frontend-design] Final Slices 10-12: Telemetry, Errors, Polish

[jayfalls]

Summary

Completes the frontend-design unit by implementing the final slices (10, 11, 12).

Slice 10: Telemetry Pages - Real Data Visualization

New Files:

• src/lib/api/telemetry.ts - API functions for spans, metrics, usage, health
• src/lib/components/telemetry/HealthCards.svelte - Health status cards (Database, NATS, Cache)
• src/lib/components/shared/DataState.svelte - Loading/error/empty/success state wrapper
• src/lib/components/shared/Pagination.svelte - Page numbers with prev/next

Updated:

• src/routes/(app)/telemetry/+page.svelte - Real health data with tabs
• src/routes/(app)/+page.svelte - Added HealthCards to dashboard

Slice 11: Error Pages

New Files:

• src/routes/(errors)/404/+page.svelte - "Page not found" with Go Home/Go Back buttons

Slice 12: Polish & Integration

New Files:

• src/lib/components/ui/toaster/Toaster.svelte - Toast notifications with auto-dismiss
• src/test/integration/auth.test.ts - Auth flow integration tests (login → dashboard → logout)

Updated:

• src/routes/+layout.svelte - Added <Toaster /> for global notifications
• src/lib/components/ui/button/button.svelte - Added aria-current prop for accessibility

Test Results

• 210 tests passing (19 test files)
• svelte-check: 0 errors, 3 warnings (pre-existing)
• Build: Success

All 12 Slices Now Complete

Slice	Status
1-6	✅ Theme, API, Forms, UI, Layout
7	✅ OS-Style Auth (username/PIN)
8	✅ Dashboard & Profile
9	✅ Admin User Management
10	✅ Telemetry Visualization
11	✅ Error Pages
12	✅ Integration Tests & Polish

Frontend Unit Complete! 🎉

The frontend now includes:

• ✅ 21 theme presets with dark/light mode
• ✅ OS-style authentication (username/PIN)
• ✅ Complete layout system (sidebar, responsive)
• ✅ All auth pages (login, register, setup)
• ✅ Dashboard with health monitoring
• ✅ User profile & session management
• ✅ Admin panel with user CRUD
• ✅ Telemetry dashboard
• ✅ Settings page with theme selector
• ✅ Error pages (404)
• ✅ Toast notifications
• ✅ 210 passing tests