Fix battery charging: limit max_charging_current to PV surplus ...

When PV can charge battery without grid (Battery First mode),
limit battery_max_charging_current = (PV - Load) / V_bat to prevent
battery from pulling excess power from grid.

Without this fix, battery charged at max 100A even when PV surplus
was only ~55A, resulting in ~500W grid import for battery charging.

Formula: max(5, min(100, (pv_w - load_w) / bat_voltage_v))
Applied in both g12w_wlacz_ladowanie_dzienne and g12w_pv_charging_optimization.
On grid-charge path: restore battery_max_charging_current to 100A.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

G12W: Smart afternoon charging - use grid only when PV can't charge battery ...

Replaces fixed-threshold logic with energy budget calculation:
- Formula: PV_surplus_W * remaining_hours >= battery_deficit_Wh
- Battery capacity: 14336 Wh (280Ah LFP at 51.2V nominal)

'Włącz ładowanie dzienne 13:00' (12:55 trigger):
- Calculates if PV surplus over full 2h window >= battery deficit
- YES → Battery First, no grid charging needed
- NO → Load First + Grid at 100A (use cheap G12W tariff)

'Optymalizacja PV ładowania dziennego' (every 15min, 13:00-15:00):
- Recalculates with actual remaining time in window
- Dynamically switches between Battery First / Grid as cloud cover changes
- Only triggers grid charging when SOC < 95% and PV genuinely can't finish the job

Example: PV=3358W, Load=1188W, SOC=99%, remaining=1.38h
  Surplus=2988 Wh >> Deficit=143 Wh → Battery First, grid import drops 3100W→324W

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

G12W: Ładowanie 13:00-15:00 zawsze w dni robocze ...

Usunięty warunek prognozy < 5 kWh dla dziennego ładowania.
Teraz automatyzacja uruchamia się zawsze Pn-Pt gdy SOC < 95%.

Add G12W battery automation, IBSystem MQTT integration, HA configs ...

Zmiany:
- ha-configs/151/: Kopia konfiguracji HA TEST
  - automations.yaml: Automatyzacje G12W ładowania baterii
  - configuration.yaml: Główna konfiguracja z dashboardami
  - dashboards/: Deye, Ogrzewanie, IBSystem, ID35

- ibsystem/: Integracja IBSystem z MQTT
  - ibsystem2mqtt_v5.py: Bridge IBSystem → MQTT
  - config.yaml: Konfiguracja połączeń
  - ibsystem2mqtt_watchdog.sh: Health check i auto-restart

- docs/: Dokumentacja
  - G12W_BATTERY_AUTOMATION.md: Opis taryfy i automatyzacji
  - IBSYSTEM_MQTT_INTEGRATION.md: Opis integracji MQTT

Kluczowe naprawy:
- Program 6 Deye: zmiana z 21:00 Disabled na 22:00 Grid
- IBSystem: setting.light.X zamiast output.do.X dla sterowania
- Dashboard ID35: prawidłowe entity IDs (ibsystem_rs0_id35_*)
- Watchdog dla ibsystem2mqtt (cron co minutę)