Faze 0A: battery guard carve-out — neblokovat import na nabiti pri zaporne cene

_apply_export_plan_guard / _build_setpoints: kdyz slot CHARGE / importuje na
nabiti baterie (grid_sp>0 & bat>0), guard vrati sp beze zmeny a export_ban se
nenastavi. Opravuje, ze se baterie nedobila v zapornych cenach (CHARGE+17kW
prekloplen na PASSIVE -> Deye nenabijel ze site). Diagnoza: agent a599eecc.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/services/control/setpoints.py

@@ -125,11 +125,20 @@ def _build_setpoints(
             export_limit = 0
         elif export_limit <= 0 and grid_sp < 0:
             export_limit = abs(grid_sp)
+        bat_w = int(pi["battery_setpoint_w"] or 0)
         # Záporný výkup sám o sobě neblokuje export, pokud plán export explicitně žádá.
-        export_ban = sell_f is not None and float(sell_f) < 0 and grid_sp >= 0
+        # A nesmí blokovat ani IMPORT na nabití baterie (CHARGE / grid>0 & bat>0) —
+        # jinak MI cut-off (178) / 145=0 zbytečně odstaví pole B a Deye nenabije
+        # ze sítě v záporných cenách (bug 2026-06-13). §6 blokuje jen export.
+        is_grid_charge = pm == "CHARGE" or (grid_sp > 0 and bat_w > 0)
+        export_ban = (
+            sell_f is not None
+            and float(sell_f) < 0
+            and grid_sp >= 0
+            and not is_grid_charge
+        )
         gen_cutoff_raw = pi.get("deye_gen_cutoff_enabled")
         gen_cutoff = bool(gen_cutoff_raw) if gen_cutoff_raw is not None else False
-        bat_w = int(pi["battery_setpoint_w"] or 0)
         pv_a_allowed: int | None = None
         if bool(reg340_pv_a_control_enabled) and int(pv_a_cap_w) > 0:
             forecast = int(pi.get("pv_a_forecast_solver_w") or 0)
@@ -294,6 +303,16 @@ def _apply_export_plan_guard(
     )
     grid_sp = int(pi.get("grid_setpoint_w") or sp.grid_setpoint_w or 0)
 
+    # Carve-out: nabíjecí / importní slot NENÍ export. Guard řeší jen zákaz
+    # exportu při sell<0 — když plán importuje na nabití baterie (CHARGE, nebo
+    # grid_sp>0 & bat_sp>0), překlopení na PASSIVE by zařízlo grid charge
+    # (bug 2026-06-13: baterie se nedobila v záporných cenách). §6 zakazuje
+    # jen export, ne import (§7).
+    pm = str(pi.get("deye_physical_mode") or "").strip().upper()
+    bat_sp = int(pi.get("battery_setpoint_w") or 0)
+    if pm == "CHARGE" or (grid_sp > 0 and bat_sp > 0):
+        return sp
+
     neg_sell = sell_f is not None and float(sell_f) < 0
     plan_no_export = export_mode == "NONE" and grid_sp >= 0
     if not neg_sell and not plan_no_export:

backend/tests/test_control_export_plan_guard.py

@@ -111,6 +111,29 @@ class ExportPlanGuardTests(unittest.TestCase):
         self.assertIs(out, sp)
         self.assertEqual(get_deye_mode(out), "SELL")
 
+    def test_neg_sell_grid_charge_not_blocked(self) -> None:
+        # Záporný sell + IMPORT na nabití baterie (CHARGE / grid>0 & bat>0):
+        # guard NESMÍ překlopit na PASSIVE — jinak Deye nenabije ze sítě
+        # v záporných cenách (bug 2026-06-13).
+        sp = _sp(
+            grid_setpoint_w=17000,
+            battery_w=17000,
+            deye_physical_mode="CHARGE",
+            export_mode="NONE",
+        )
+        pi = _DictRecord(
+            {
+                "grid_setpoint_w": 17000,
+                "battery_setpoint_w": 17000,
+                "deye_physical_mode": "CHARGE",
+                "effective_sell_price": -1.2,
+                "export_mode": "NONE",
+            }
+        )
+        out = _apply_export_plan_guard(1, _auto_mode(), pi, sp)
+        self.assertIs(out, sp)
+        self.assertEqual(get_deye_mode(out), "CHARGE")
+
     def test_non_auto_mode_skipped(self) -> None:
         sp = _sp()
         pi = _DictRecord({"effective_sell_price": -1.0, "export_mode": "NONE"})