feat: store adapter — redux/zustand writers ↔ readers (C6)

[officialCodeWork]

Summary

TRACKER Step 2.4 — failure mode C6, temporal decoupling. The hardest attribution case after C1: a component reads useSelector(s => s.users.list) and contains no fetch at all — the API that populated the slice was dispatched at login, by a different component, on a different page.

UserDirectory ──reads-state──▶ slice "users" ◀──writes-state── GET /api/users
                                                    ▲
                          createAsyncThunk payload ─┘  (dispatched by LoginPage)

traceLineage(UserDirectory) → /api/users. traceLineage(LoginPage) → /api/users too (it initiates the fetch via dispatch(fetchUsers())).

What's detected

• Redux Toolkit — createSlice (one global StateNode per slice), createAsyncThunk (payload creator mined with the full 1.x endpoint machinery), extraReducers addCase(thunk.fulfilled) association → writes-state edges
• Zustand — create() stores named use*; internal fetches become writers; hook calls become readers
• Readers — useSelector slice-path parsing links to the global slice node (old per-component fallback kept); dispatch(thunk()) links the dispatcher
• Core — traceLineage follows writes-state edges backward through state nodes

Eval

• New fixture c6-store-decoupled with cross-store poison assertions (redux slice's API must never bleed onto the zustand reader, and vice versa)
• Scorecard: 129 pass / 0 fail / 0 xfail · precision 1.000 · recall 1.000 · match accuracy 1.000
• 85 unit tests (5 new)

Also fixed in passing: a declaration-order bug (detectStores referenced addEdge before initialization).

Documentation

• TRACKER.md — 2.4 done, Status → 2.5 (portals — the last step before Gate 2)

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