test(fase3): SC4 shared-store accumulation + load-bearing cross-project retrieval

tests/test_portfolio.py

@@ -82,3 +82,26 @@ async def test_a2_unknown_project_id_raises(make_portfolio_client_factory, fresh
             store=fresh_store,
             client_factory=make_portfolio_client_factory(REPLIES),
         )
+
+
+async def test_b_shared_store_accumulates_and_surfaces_prior_verdict(
+    make_portfolio_client_factory, fresh_store
+) -> None:
+    """SC4 (load-bearing, not mere non-emptiness): the ONE shared store accumulates a distinct
+    verdict per project (3 -> 3 pairwise-distinct ids), and the cross-project ExpeL retrieval
+    surfaces the STRUCTURAL match — BRU (runs[2]) retrieves FV42's verdict (runs[0]), since
+    sim(BRU,FV42)=0.60 (shared code 05.2 + identical "Reduce scope" measure + same magnitude
+    bucket) ranks above the RV13 decoy at sim(BRU,decoy)=0.15. If retrieval ranking breaks, or
+    two proposals collide to a single minted id, this fails — it asserts the specific match, not
+    store-non-empty."""
+    result = await run_portfolio(
+        _PORTFOLIO_IDS,
+        "local",
+        store=fresh_store,
+        client_factory=make_portfolio_client_factory(REPLIES),
+    )
+    assert len(result.store.verdicts) == 3
+    ids = [v.id for v in result.store.verdicts]
+    assert len(set(ids)) == 3  # pairwise distinct minted ids (no collision)
+    # BRU surfaces FV42 (the structural match), ranked above the decoy.
+    assert result.runs[2].retrieved[0].id == result.runs[0].verdict.id