OPT-11 P3, owner option A: selling off, Leftover solar takes solar only

Owner decision 2026-09-29. Selling is off until it can be judged on the price
the grid pays: packmode.SELLING_ENABLED = False makes read() answer
sell=False whatever the store holds, pack_sell is refused ("Selling is off
for now."), and the page has no selling switch; the sell code stays. Until
the P4 forecast, only Cheap hours only charges from the grid
(packmode.GRID_CHARGE_MODES); Leftover solar holds and gives in the
expensive runs. Help, Today and plan lines, DOCS and DECISIONS follow.
Replay, 16 days: Solar first + Leftover solar 19.44 EUR net (P2 19.33).

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

goodwe_controller/app/main.py

@@ -2303,6 +2303,8 @@ class Controller:
                 self._maint_stop_off(self.maints[self.inverters.index(inv)],
                                      now)
         elif what == "pack_sell":
+            if not packmode.SELLING_ENABLED:
+                return {"error": messages.pack_refused("sell_off")}
             if not isinstance(value, bool):
                 return {"error": messages.pack_refused("value")}
             inv.store_set(packmode.SELL_KEY, value)