Declare the dead regime's assets grid non-distributed

The terminal `dead` regime carries only a tiny `[pref_type, assets]`
value function. Inheriting the distributed `assets` grid made its
V-array topology claim a sharded assets axis, while the solver emits a
replicated array — a mismatch that surfaces as an opaque XLA sharding
error mid-solve on multi-GPU runs. Sharding a terminal 3x24 V-array
buys nothing; declare `assets` non-distributed for `dead`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: hmgaudecker

src/aca_model/baseline/regimes/_common.py

@@ -449,7 +449,7 @@ def build_dead_regime(grids: Grids) -> Regime:
             "utility_scale_factor": preferences.utility_scale_factor,
         },
         states={
-            "assets": grids.assets,
+            "assets": grids.assets.replace(distributed=False),
             "pref_type": grids.pref_type,
         },
         active=lambda _age: True,

tests/test_model_creation.py

@@ -58,6 +58,18 @@ def test_dead_regime_is_terminal() -> None:
     assert model.user_regimes["dead"].terminal
 
 
+def test_dead_regime_assets_grid_not_distributed() -> None:
+    """The terminal `dead` regime declares its `assets` grid non-distributed.
+
+    `dead` carries only a tiny `[pref_type, assets]` value function;
+    sharding its assets axis across devices buys nothing and makes its
+    V-array sharding disagree with what the multi-GPU solve produces for
+    the regimes that transition into it.
+    """
+    dead = build_regime("dead")
+    assert dead.states["assets"].distributed is False
+
+
 def test_non_terminal_regimes_not_terminal() -> None:
     model = make_baseline_model(n_subjects=1)
     for name in REGIME_SPECS: