feat(frontend): match homepage Stars feed to Razor

[Seme30]

Part of #789.

Problem

Home tabs work on both hosts, but the Stars feed does not read as the same product.

Current gaps

On / as demo admin:

• Both greet Hi, Admin, Local! and switch Stars, Subscriptions, Report Runs, and Groups without changing the route.
• Seeded names appear on both (Daily Emergency Department Census, Improve Patient Flow, Patient Flow Command Center, Average Length of Stay, Enterprise Analytics).
• Razor Stars shows 14 cards plus a Shared With Me rail.
• Next.js Stars shows 58 in All, has no Shared With Me rail, and puts yellow card chrome on collections instead of initiatives.

Frontend / Razor references

• frontend/app/page.tsx
• frontend/components/home/
• web/Pages/Index/Index.cshtml

Definition of done

• Stars item set, folder/quick-filter counts, and Shared With Me rail match Razor for the demo-admin seed.
• Collection vs initiative card chrome matches Razor closely enough to read as the same product.
• Tab switching still lazy-loads Stars, Subscriptions, Report Runs, and Groups.
• Frontend tests cover the Stars feed structure.