OPT-11 P1: per-battery mode limits, on/off, solar order

A battery's mode is a soft unit limit (source `mode`, P_MODE 35) kept
apart from the hard limits in pre_resolve(). The allocator applies it
only while the site target is decided at or below 35 (new
Resolution.deciding_priority), so the peak floor releases it and a mode
`hi` never meets the site `lo`. At N=1 resolve() applies the same rule
to the site target after stage 2. A mode range without 0 W is dropped
as a software fault, so REFUSE_SIGN stays unreachable from a mode.

compute() gets the loop bound (sum over live units of hard limits with
modes applied), so the loop never asks for watts no battery may give
and the saturation freeze never parks on them. While charging, Leftover
solar weighs 0 so Solar first fills first. Store keys pack_use and
pack_mode per battery, set by two new /action values; Off stops and
skips maintenance with a log line. Minimal Batteries cards (EN/NL).

Off by default (battery_modes_enabled); off, commands are byte-identical
to a5dddad at N=1 and N=2 (test_modes.py part 1).

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

goodwe_controller/DOCS.md

@@ -183,6 +183,7 @@ The label and description each setting shows on the Configuration tab, in tab or
 | Hardware · Inverter list | Battery power sign is reversed (optional) | `inverters.batt_invert` | Switch this on if this inverter's sensor shows giving power as a negative number. |
 | Hardware · Inverter list | Usable battery capacity (kWh) (optional) | `inverters.capacity_kwh` | This battery's usable capacity from its datasheet. Fill it in on every inverter or on none. The add-on then shares the work by the energy each battery has left. |
 | Hardware | RS485 emergency stop is fitted | `estop_fitted` | Switch this on if the emergency stop is installed. It only changes a warning on the status page. |
+| Hardware | Battery modes | `battery_modes_enabled` | Give each battery an on and off switch and a mode, set on the Batteries screen. |
 | Hardware | Solar production entity (W) | `pv_entity` | Optional. Your solar inverter's power sensor, positive while producing. The add-on records it and does not use it for control. |
 | Hardware | Solar production entities, per inverter (W) | `pv_entities` | Optional. Use one row per solar inverter instead of “Solar production entity” when you have several. If one stops reporting, no total is recorded. |
 | Hardware | Reversed-sign solar entities | `pv_invert_entities` | Optional. Add each solar entity above that reads negative while producing, spelled the same way. Its sign is flipped before adding up. |
@@ -512,6 +513,17 @@ two of a thing there is one of, and `P1 sample age` is a safety input. Same for
 status, the maintenance phase, the capacity-tariff peak and the three loop rows
 below.
 
+### Battery modes (`battery_modes_enabled`)
+
+Off by default. Turn it on, restart the add-on, and the Batteries screen gives each battery two controls. They apply at once, with no restart.
+
+- **On or off.** Off asks the battery for 0 W and starts no monthly cycle on it. A cycle that is running stops, and the add-on log says so. The peak limit may still use it, like every battery.
+- **Mode.** *Solar first* charges from spare solar before the other batteries. *Leftover solar* charges from the solar they cannot take. Both cover the house at any hour. Charging from the grid in cheap hours, and selling, come in a later update.
+
+The peak limit, the safety stops and the monthly cycle always come before a battery's mode.
+
+*For installers:* a mode is a limit at priority 35, kept apart from the hard limits, and released whenever a claim above it (the peak guard) decides the site target. A mode range always holds 0 W, so a mode can forbid a direction and never force one. With one inverter the mode also bounds the loop. The record is `DECISIONS/OPT-11-battery-modes.md`.
+
 ### Reading the grid-following loop: `Loop integrator`, `Loop integrator lead`, `Loop reason`
 
 The control law is a bounded integrator: an accumulator that is **not** the