⭐ Store

@ngrx/store, added first — real source, 790/790 tests passing, 0 lint errors. The module carrying this repo's core architectural decision: Store, ActionsSubject, ReducerManager, State, and ScannedActionsSubject all originally extended RxJS Observable/Subject types directly, redesigned to composition across 3 audit passes. See Composition over Inheritance for why.

Code review complete: 27/27 files, 3 real bugs found and fixed — freeze(), getUnserializable(), and combineReducers() each missing a null-state guard their own recursive logic already had, all inherited from the original upstream import — plus 1 test-coverage gap closed (provideState()'s multi-feature wiring had zero coverage despite looking like a real bug on first read). See Code Review Audit and docs/code-review.md.