refactor(font): expose stores via model segment, not the top barrel

Re-exporting the store singletons (fontCatalogStore, fontLifecycleManager,
FontsByIdsStore) through entities/Font/index.ts meant every consumer of the
barrel eager-instantiated stores and pulled @tanstack/query-core — in dev,
test, and as retained code. Drop the store re-export from the top barrel;
keep the pure surface (types, constants, domain, lib, ui) there for
convenience. Consumers that need stores import $entities/Font/model.
Aligns with the BaseQueryStore carve-out: barrel by default, segment path
when it would drag a heavy or side-effectful dependency.

src/entities/Font/index.ts

@@ -1,8 +1,21 @@
 export * from './api';
 export * from './domain';
 export * from './lib';
-export * from './model';
 export * from './ui';
 
+// Pure model surface (types + constants) is part of the convenient top-level
+// API. Stateful stores are deliberately excluded — see below.
+export * from './model/const/const';
+export * from './model/types';
+
+/*
+ * Stores (`fontCatalogStore`, `fontLifecycleManager`, `FontsByIdsStore`) are
+ * intentionally NOT re-exported here. They instantiate module-level singletons
+ * and pull `@tanstack/query-core`, so funneling them through this barrel would
+ * make every consumer of `$entities/Font` eager-instantiate stores (and break
+ * tree-shaking / test init-order). Import them via the model segment:
+ *   import { fontCatalogStore } from '$entities/Font/model';
+ */
+
 // `./testing` is intentionally not re-exported: fixtures must not leak into the
 // production public API. Import them via `$entities/Font/testing`.