MAINT-11: start or stop the maintenance cycle per battery

maint_start and maint_abort take an optional unit. With two or more batteries
each Batteries card has Start cycle and Stop cycle buttons. One slot per site
stays: a start while a battery cycles is refused and names it (no queue). A
battery that is switched off, an unknown unit, and a stop on a battery that is
not cycling are refused with a plain message. A request with no unit is the
old call. The scheduler and the phase machine are unchanged.

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

goodwe_controller/app/ui_text/en.json

@@ -92,6 +92,7 @@
         "off": {"name": "Off", "description": "Rests, and helps only when the peak limit needs it."}
       },
       "today": "Today", "why": "Why",
+      "cycle": {"start": "Start cycle", "abort": "Stop cycle", "start_dialog": {"name": "Start a cycle on {name}?", "description": "{name} empties, refills and holds full, which takes a few hours.", "yes": "Start the cycle"}, "abort_dialog": {"name": "Stop the cycle on {name}?", "description": "Every inverter is set to 0 W for a moment, then control carries on.", "yes": "Stop the cycle"}, "toast": {"started": "Cycle started on {name}.", "stopped": "Cycle stopped on {name}."}, "unit": {"description": "There is no battery with that name."}, "busy": {"description": "Only one battery can cycle at a time, and {name} is cycling now."}, "off": {"description": "{name} is switched off, so it cannot start a cycle."}, "idle": {"description": "{name} is not running a cycle."}},
       "modes_off": {"name": "Battery modes are off"},
       "how": {"name": "How the modes work", "description": "Which battery gets solar first, and when each gives power.",
         "solar_first": {"description": "Solar first gets spare solar before the other batteries, and covers the house at any hour."},