fix(gateway): bind battery_scaling, battery_rate_max and inverter_time per inverter

[springfall2008]

Problem

On a PredBat Gateway (Hub) site with two or more primary inverters, GatewayMQTT.automatic_config() bound three per-inverter args to the first inverter only:

self.set_arg("battery_scaling", [f"sensor.{base0}_battery_dod"])
self.set_arg("battery_rate_max", [f"sensor.{base0}_battery_rate_max"])
self.set_arg("inverter_time", [f"sensor.{base0}_inverter_time"])

inverter.py reads all three at index=self.id. So for inverter 1 onwards:

• Every cycle logs Warn: Out of range index 1 within item battery_rate_max / battery_scaling / inverter_time, and config validation reports 3 errors (… has 1 entries, expected 2 based on num_inverters).
• battery_rate_max silently falls back to 2600 W. In the field case (2 × GivEnergy AC Gen1 behind a Hub) the hub reports 3000 W for the second inverter, so PredBat planned that battery about 13% slower than it is and sent set_charge_rate power_w: 2600.
• battery_scaling falls back to 1.0. That happens to match the hub's default 100% depth of discharge, but it isn't read from the hub.
• inverter_time is never read for that inverter, so its clock-drift check doesn't run.

Every other per-inverter arg (soc_percent, battery_power, charge_rate, inverter_limit, …) is already built in the per-inverter loop. These three were left over from the single-inverter version.

Fix

Build the three lists inside the existing per-inverter loop, so each has one entry per primary inverter, in the same serial-sorted order as soc_percent. The hub already publishes battery_dod, battery_rate_max and inverter_time for every inverter. This was confirmed on the field instance, where both …_23g800_* and …_25g400_* exist with live values. So no gateway-side change is needed.

Single-inverter sites, and the Gateway-coordinated topology where automatic_config picks the Gateway as the sole control target, still get a one-entry list bound to the same serial as before. test_single_inverter_energy_and_health_args and TestBoundEntitiesAreWritten cover those cases and still pass.

Tests

• New TestAutomaticConfig.test_multi_inverter_battery_args_have_one_entry_per_inverter: two primary inverters, and asserts each of the three args lists both inverters' entities in order. It failed before the fix (battery_scaling had a single entry) and passes after.
• ./run_all --test gateway: passed.
• ./run_all --quick: All tests passed (4 slow tests skipped, 80.95s).
• pre-commit (ruff, black, cspell, whitespace): passed.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟢 Approval recommended

The focused fix matches indexed inverter reads and includes appropriate regression coverage.

Review effort: Balanced
Findings: None

What changed in this PR

Fixes Gateway multi-inverter configuration so each inverter receives its own battery and clock entities.

Changes:

• Builds three per-inverter entity lists in serial-sorted order.
• Adds regression coverage for two primary inverters.

File	Description
apps/​predbat/​gateway.py	Binds battery scaling, maximum rate, and inverter time per inverter.
apps/​predbat/​tests/​test_gateway.py	Verifies multi-inverter bindings and ordering.

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