OPT-11 P3 review: sale shows no money, honest sell text, tests for four surviving mutants

- A sale block on the plan no longer says "Worth up to" at the import
  price: a sale earns the lower injection price.
- The selling switch help (EN/NL) and DOCS say the grid pays less than
  power costs; DECISIONS records why P3 loses on the replay.
- test_modes_p3 part 11: modes on ignore the site trade switch (R13), a
  battery in maintenance takes no part (R10), a headroom stop latches for
  the period (R8). All three mutants survived before and are red now.

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

goodwe_controller/DECISIONS/OPT-11-battery-modes.md

@@ -51,12 +51,22 @@ P1 is its section 6 P1, and the pull request lists what was measured.
     on flat morning prices, then charging went on at them);
   - a run edge reseeds the loop at the house's level (a 3 kW import spike
     removed; about 0.1 x rating still overshoots as export).
-- Replay (tools/opt11p3_replay.py, 16 recorded days, EPEX prices a year
-  earlier, modelled batteries): P3 does not beat the P2 baseline on money
-  (net 19.57 / 19.60 EUR against 19.33; the old one-period trade 18.14).
-  A sale is judged on import prices but exports earn the injection price,
-  so selling lost money in the model. The owner should see this before
-  selling is recommended.
+- Replay (tools/opt11p3_replay.py, 16 recorded days, EPEX hourly prices a
+  year earlier, modelled batteries), net EUR, lower is better: P2 19.33, P3
+  Solar first + Leftover solar 19.57, with a sale 19.60, the old one-period
+  trade 18.14. Review of #153 (same model, with a per-action split):
+  - the cheapest hours were at midday on 15 of 16 days, so Leftover solar (acting
+    as Cheap hours until P4) bought 12.2 kWh there that the sun would have
+    given: 7 kWh more exported, 12 kWh less solar stored. Holding for the
+    expensive hours saved 4 kWh of import, not enough. With no grid charge on
+    Leftover solar: 19.44;
+  - the old trade charged one hour, so the afternoon sun still fit;
+  - a sale earned the wholesale price (2.27 EUR for 11.4 kWh) and the house
+    then bought the same energy back (2.29 EUR): a wash before wear. It pays
+    only when the sale hour's wholesale price beats the later import price,
+    levies included (about 0.13 EUR/kWh above that hour's wholesale here);
+  - valuing the charge left at the end, wear and real Flemish levies make
+    selling worse and do not change the order.
 - Not done in P3: the forecast (P4: Leftover solar acts as Cheap hours only),
   a headroom too short for the run moving the rest to the next cheap periods,
   and an HA switch for selling.