Function InstallApp

Executes the full install flow for an Open App.

Every capability block is optional and additive: an app may extend MJ via a schema, metadata, packages, any combination, or be manifest-only. Each step below is gated on its block being present, so a manifest-only app simply records itself and finishes. The persisted MJ: Open Apps.ManifestJSON is the source of truth re-read by upgrade/remove.

Steps (each no-ops when its block is absent):

1. Fetch manifest from GitHub
2. Validate manifest (Zod)
3. Validate MJ version compatibility
4. Resolve the FULL transitive dependency graph (fetch every dependency's manifest, detect cross-repo cycles, topologically sort) — skipped when this call is itself a pre-resolved member of a parent's graph
5. Install dependencies in leaf-first order (each via _skipDependencyResolution)
6. Check schema (no collision)
7. Create schema
8. Run migrations (Skyway - DDL + metadata DML)
9. Record installation with 'Installing' status
10. Update package.json files
11. Run npm install
12. Update server + client config (dynamicPackages.server/.client in mj.config.cjs; client imports are materialized into MJExplorer's manifest at its next prebuild)
13. Update angular.json prebundle excludes (prevents Vite singleton duplication)
14. Execute hooks (postInstall)
15. Finalize status to 'Active'