UX-54 round 5: give blocks end at the floor point, the tab on the clock-change days

daycurve.curve() puts a point where a giving battery reaches the floor
inside a step (_floor_cut(), as it already does for a grid charge reaching
its level), so _stops() ends a give block in the quarter control stops. A
walk where control moves the packs with its own model (not the curve's
levels) matches the tab quarter by quarter in 11 cases; 25/45 % with the
peak guard: control 17:00-20:15, block 17:00-20:06.

SolarToday keys an hour by its start taken back from the UTC instant, so
the two 02:00 hours of the autumn change stay apart. test_ux54_dst.py builds
the tab (forecast_payload()) at every quarter of 27-29 March and
30 October-1 November 2027, modes on and off, in the no-tzdata zone and,
where the host has tzdata, ZoneInfo, every call under a time limit raised
as a BaseException that forecast_payload() cannot swallow.

give_later: "No block shows while a battery has no energy to give." /
"Er verschijnt geen blok zolang een batterij niets kan leveren."
DECISIONS: what the walks prove, the modes-off charge drawn on a sunny day,
the clock-change days.

No decision, command, timing or option key changes.

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

goodwe_controller/app/ui_text/en.json

@@ -456,7 +456,7 @@
       "measured_from": "Measured solar is counted from {at}, when the add-on started.",
       "tomorrow_total": "Solar expected tomorrow: {kwh}, we count on {count}.",
       "no_blocks": "No charge or give blocks planned.",
-      "give_later": "The add-on plans to give power. No block shows while the battery has no energy to give.",
+      "give_later": "The add-on plans to give power. No block shows while a battery has no energy to give.",
       "ahead": "The add-on plans about a day ahead. Blocks for later hours appear as they come near."
     },
     "region": {