fw-01 step 03 — Read Redux end to end

Goal

The Level-1 rung of the reading ladder: understand an entire production library, with no line you cannot explain.

Tasks

1. Build stages 4–8 of the build order first: enhancers, selectors with memoisation, action/state recording, time travel, persistence. Write your own tests for these — the provided spec deliberately stops at stage 5.
2. Read Redux's source end to end. Account for every difference from your implementation. There should be no line you cannot explain.
3. Answer the eight gate questions for createStore.
4. Complexity notebook: middleware vs enhancers. Why do both exist when enhancers are strictly more powerful? Answer in terms of composability and failure modes, not preference.
5. Log the reading in the shared learning log, with the "what surprised me" column filled honestly.

Done when

• Every difference from Redux enumerated and explained
• Eight gate questions answered
• Notebook entry written
• Time travel working — and you can explain why it is nearly free here and expensive in fw-03