OPT-15 review: pin the rolled export at 0 W and a battery past E; note the maintenance replay

Two survivors of the review's mutations get a check each in
test_price_run_fixes.py (X1: a held export credited negative in the rolled
quarter; X4: the hold extended by a reading already past E). DECISIONS: the
slow-battery quarter (3456 W, same on e3e4ba6) and the replay of a
maintenance phase starting during the hold.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

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

@@ -127,8 +127,11 @@ P1 is its section 6 P1, and the pull request lists what was measured.
     before its end (two inverters, lagged readings): the hold adds at most
     +33 W to that quarter against the loop without it, and the most any
     quarter banks is 3431 W with the charge sized to the aim (3450 W; the cap
-    is 3500 W). The import during the hold is the rise, below the charge's
+    is 3500 W), 3456 W with a slow 8 s battery (the lag's own, the same on
+    e3e4ba6). The import during the hold is the rise, below the charge's
     own, and a rise past that is the peak floor's, which ends the hold.
+    A maintenance drain, hold or charge that starts during the hold ends it
+    on that tick (replayed at edge + 3 s).
 
 ## P4: the solar forecast and the day plan (2026-09-29)
 - Input: a Home Assistant forecast sensor (`pv_forecast_entity`, kWh left