SAFETY-83: peak guard outranks the maintenance drain at N=1

At N=1 the drain is the site SET at P_MAINTENANCE (60), so the peak floor
(P_PEAK, 50) was not applied and the house imported what the drain left.
Where the floor asks for more than the drain rate, main.py now refiles the
peak claim at P_MAINTENANCE, so it wins; safety SETs still park everything.
Nothing else changes: safety78_identity --diff against 35cdffe changes only
cycles where the guard wanted more than the drain; N=2 is byte-identical.

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

goodwe_controller/DOCS.md

@@ -1626,7 +1626,7 @@ help - see "Why the tuning is what it is".
 | `maintenance_enabled` | false | Enable the monthly cycle |
 | `maintenance_interval_days` | 28 | Minimum gap between cycles |
 | `maintenance_start_hour` | 10 | Hour of day a due cycle begins |
-| `maintenance_discharge_w` | 2000 | Drain rate (exports the surplus). Above `max_w` it is **clamped** to `max_w` — the drain phase SETs the setpoint and the arbiter bounds it, saying so on the status page (`limited by supervised(max_w)`). Warned about, not refused: the cycle still completes, just slower |
+| `maintenance_discharge_w` | 2000 | Drain rate (exports the surplus). The peak guard may ask for more (SAFETY-83). Above `max_w` it is **clamped** to `max_w` — the drain phase SETs the setpoint and the arbiter bounds it, saying so on the status page (`limited by supervised(max_w)`). Warned about, not refused: the cycle still completes, just slower |
 | `maintenance_charge_w` | 2000 | Charge ceiling, capped again by peak headroom. Must stay **at or below `max_w`** or the cheap-window shaping (`hi = -maintenance_charge_w`) contradicts the supervised limit (`lo = -max_w`), the arbiter resolves it to **0 W**, and maintenance silently never charges in a cheap window — **the add-on refuses to start** |
 | `maintenance_soc_floor` | 11 | Drain target — stay just above the inverter's own floor. ⚠️ **This is not `peak_soc_floor`.** It is the depth the monthly recalibration deliberately goes to, once, on purpose; `peak_soc_floor` is the depth a money-saving discharge may never reach on any day. The right values differ (11 vs 20 as shipped), which is why they are two keys |
 | `maintenance_soc_target` | 99 | Charge target |
@@ -1651,6 +1651,8 @@ maintenance schedule.
 With two or more batteries, the one being emptied gives its drain rate and the
 others only add power when the house needs more; none charges while it drains
 (SAFETY-78). Below the drain rate the rest is exported, as with one battery.
+If the house would still go over the peak limit, the battery being emptied
+gives more than its drain rate, with one battery too (SAFETY-83).
 
 #### Capacity-tariff exposure of the grid-following loop