fix(compare): restore the plan in force's pre-clip copy after the tariff comparison

Plan selection scores the pre-clip version of each plan (#4403), keeping the plan in force's copy in plan_preclip
for the next re-plan to score as the previous plan. The tariff comparison runs calculate_plan() for every tariff,
each replacing plan_preclip with that tariff's 48-hour plan, and restored the windows and limits but not
plan_preclip. The first re-plan after the midnight comparison therefore scored the last tariff's plan as the plan
in force: on 9 Oct 2026 (Sigenergy, IOG) live scored its previous plan at 300.97p where the same plan scores 30.71p
without the comparison, and so switched plans regardless of metric_min_improvement_plan.

Found with the forward log replay (#5363): running the comparison inside the replay reproduced the inflated score,
and restoring each attribute the comparison changes, group by group, isolated plan_preclip. run_all() now saves and
restores it with the windows; a test runs run_all() with a tariff that replaces it and checks it comes back (it
fails without the fix).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: chalfontchubby

apps/predbat/compare.py

@@ -618,6 +618,9 @@ def run_all(self, debug=False, fetch_sensor=True):
         save_export_window_best = my_predbat.export_window_best
         save_export_limits_best = my_predbat.export_limits_best
         save_charge_limit_best = my_predbat.charge_limit_best
+        # The pre-clip copy of the plan in force, which the next re-plan scores as the previous plan; each tariff's
+        # calculate_plan() replaces it with its own plan
+        save_plan_preclip = my_predbat.plan_preclip
         save_cost_today_sofar = my_predbat.cost_today_sofar
         save_carbon_today_sofar = my_predbat.carbon_today_sofar
         save_iboost_today = my_predbat.iboost_today
@@ -735,6 +738,7 @@ def run_all(self, debug=False, fetch_sensor=True):
             my_predbat.export_window_best = save_export_window_best
             my_predbat.export_limits_best = save_export_limits_best
             my_predbat.charge_limit_best = save_charge_limit_best
+            my_predbat.plan_preclip = save_plan_preclip
             my_predbat.cost_today_sofar = save_cost_today_sofar
             my_predbat.carbon_today_sofar = save_carbon_today_sofar
             my_predbat.iboost_today = save_iboost_today

apps/predbat/tests/test_compare.py

@@ -68,10 +68,54 @@ def _make_compare():
     return cmp, pb
 
 
+def test_run_all_restores_plan_preclip(my_predbat):
+    """run_all() puts back the pre-clip copy of the plan in force, which each tariff's calculate_plan() replaces.
+
+    Left as the last tariff's 48-hour plan, the first re-plan after the midnight comparison scored that plan as the
+    previous one, so it always switched plans whatever metric_min_improvement_plan said (seen live on 9 Oct 2026:
+    previous plan 300.97p against 30.71p when the comparison is not run).
+    """
+    from compare import Compare
+
+    saved_compare_list = my_predbat.args.get("compare_list")
+    saved_preclip = my_predbat.plan_preclip
+    plan_in_force = ([18.08], [{"start": 0, "end": 90, "average": 7.62}], [], [])
+    my_predbat.plan_preclip = plan_in_force
+    my_predbat.args["compare_list"] = [{"id": "test_tariff", "name": "Test tariff"}]
+    comparison = Compare.__new__(Compare)
+    comparison.pb = my_predbat
+    comparison.log = my_predbat.log
+    comparison.comparisons = {}
+
+    def run_single(*args, **kwargs):
+        """Stand in for a tariff's run: its calculate_plan() replaces plan_preclip with that tariff's plan."""
+        my_predbat.plan_preclip = ([0.0], [{"start": 0, "end": 2880, "average": 30.0}], [], [])
+        return None
+
+    comparison.run_single = run_single
+    comparison.select_best = lambda *args, **kwargs: None
+    comparison.save_yaml = lambda *args, **kwargs: None
+    comparison.publish_data = lambda *args, **kwargs: None
+    try:
+        comparison.run_all(fetch_sensor=False)
+        if my_predbat.plan_preclip is not plan_in_force:
+            print("ERROR: run_all() should restore the plan in force's pre-clip copy, got {}".format(my_predbat.plan_preclip))
+            return 1
+        print("PASS: run_all() restores plan_preclip")
+        return 0
+    finally:
+        my_predbat.plan_preclip = saved_preclip
+        if saved_compare_list is None:
+            my_predbat.args.pop("compare_list", None)
+        else:
+            my_predbat.args["compare_list"] = saved_compare_list
+
+
 def test_compare(my_predbat):
     """Run all compare unit tests."""
     failed = 0
     print("**** Running compare tests ****\n")
+    failed += test_run_all_restores_plan_preclip(my_predbat)
 
     # ------------------------------------------------------------------
     # T1: apply_hardware_overrides – soc_max override