feat(mvp): phase 4 - app registry & healthcheck

Add app CRUD API endpoints, healthcheck service with node-cron scheduler,
icon resolver (Lucide, Simple Icons, CDN, uploads), app management UI
with Superforms, health badge component, and Docker health endpoint.

plans/mvp-web-app-launcher/PLAN.md

@@ -30,7 +30,7 @@ Build a self-hosted web application launcher/dashboard for a TrueNAS server envi
 - [x] Phase 1: Project Scaffolding & Tooling [backend] → [subplan](./phase-1-scaffolding.md)
 - [x] Phase 2: Database Schema & Services Layer [backend] → [subplan](./phase-2-database-services.md)
 - [x] Phase 3: Authentication System [fullstack] → [subplan](./phase-3-authentication.md)
-- [ ] Phase 4: App Registry & Healthcheck [fullstack] → [subplan](./phase-4-app-healthcheck.md)
+- [x] Phase 4: App Registry & Healthcheck [fullstack] → [subplan](./phase-4-app-healthcheck.md)
 - [ ] Phase 5: Board, Section & Widget System [fullstack] → [subplan](./phase-5-board-widgets.md)
 - [ ] Phase 6: Admin Panel [fullstack] → [subplan](./phase-6-admin-panel.md)
 - [ ] Phase 7: UI Polish & Ambient Backgrounds [frontend] → [subplan](./phase-7-ui-polish.md)
@@ -43,7 +43,7 @@ Build a self-hosted web application launcher/dashboard for a TrueNAS server envi
 | Phase 1: Scaffolding | backend | ✅ Complete | ✅ | ⬜ | ⬜ |
 | Phase 2: Database & Services | backend | ✅ Complete | ⬜ | ⬜ | ⬜ |
 | Phase 3: Authentication | fullstack | ✅ Complete | ⬜ | ⬜ | ⬜ |
-| Phase 4: App & Healthcheck | fullstack | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
+| Phase 4: App & Healthcheck | fullstack | ✅ Complete | ⬜ | ⬜ | ⬜ |
 | Phase 5: Board & Widgets | fullstack | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
 | Phase 6: Admin Panel | fullstack | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
 | Phase 7: UI Polish | frontend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |