Problem: the frontend had an implicit OS+Apps metaphor (desktop, floating
windows, an app registry) but the contract was informal — the mascot was
hardcoded into the shell, all apps were statically imported into one
800KB bundle, and there was no install/uninstall path.
Change: three phases landed.
- Phase 1 (contract + docked kind): AppDef extended with docked/noIcon
and optional geometry; the mascot registered as a docked app via a
generic DockedLayer that replaces the hardcoded <MascotLayer />;
openAppWindow branches on docked → toggleDocked; persisted docked
visibility store (absent key = visible, no APPS import to avoid a
static cycle).
- Phase 2 (lazy loading): AppDef.component is now a dynamic-import
loader; LazyApp renders with a loading skeleton; Vite code-splits
each app (main bundle 800KB→485KB); the LazyMascot wrapper is gone
since the lazy loader breaks the import cycle directly.
- Phase 3 (installable apps, local bundles): AppManifest + catalog +
installApp/uninstallApp + localStorage persistence; reactive apps
store (built-in + installed) and derived appById; App Store page;
Notes demo app; icons.ts and WindowLayer's orphan-close react to
registration so installs appear without a reload.
- Structure: data-table casing unified to PascalCase; the mislabeled
DataTable.svelte.ts (pure types, not runes) renamed to types.ts;
LazyApp colocated with its desktop-shell consumers; app-store moved
under lib/ so the dependency direction is consistent.
Risk: the app registry is now a reactive store, not a static array, so
every consumer (Desktop, DockedLayer, Taskbar, icons, windows) reads
from derived stores. Two static-cycle traps are documented in
docs/mbse/components.md §9: docked.ts must not import APPS (it would
fire a TDZ at init via the apps.ts→pages→windows.ts→here path), and
apps.ts must not statically import the mascot (the lazy loader defers
its module graph). Remote bundle loading, the /api/v1/apps endpoint,
and permission enforcement are deliberately NOT in this commit — they
are security-critical and deferred to Phase 4 with an ADR.
Verification: vitest 38/38; svelte-check + tsc clean for changed files;
eslint clean; vite build green; runtime smoke confirmed (install
Notes → icon appears → open → uninstall → icon + window gone; survives
reload). docs/mbse/components.md Component 9 and the plan updated.
Plan: plans/2026-07-21-frontend-os-apps-architecture.md
dtoro
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