UX-13 P2: the Installer settings view

- Settings tab: the Installer view (app/static/settings.js), drawn from
  app/uilayout.py through the new app/uipage.py: search, six collapsible
  groups with "n to fix / n to check / n changed" badges and an "applies
  after a restart" chip, radio cards, segmented choices, sliders with units
  (the peak limit in kW), entity pickers with search and the live reading,
  inverter cards, solar rows, locked measured values behind "Change", and
  the add-on's refusals, warnings and info beside the field they name.
- Save path: the page posts its model to the existing config/validate and
  config/save; uimodel turns it into options before the shipped validator,
  so nothing it refuses is saved. No route added. A value equal to the
  stored one is written as stored, so a save that changed nothing writes an
  identical blob. Save bar, then the restart dialog that names 0 W.
- The region choice shows its preset year; Wallonia and Brussels are listed
  as having no preset yet (TARIFF-22). "Classic settings" keeps /config.
- P1 test findings: (a) "Going to 0 W" until the last accepted power request
  is 0 W; (b) the trade blocks and the price line name the feed's own points
  ("Lowest published price"), the hour bars say "hour average"; (c) the entity
  list's WARNING gives a reason on a timeout.
- test_settings.py; test_home, test_haentities, test_uilayout extended.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LyR88rXETvwhTgx6yHE39p

goodwe_controller/app/uilayout.py

@@ -43,6 +43,8 @@ class Field:
     applies: str = RESTART
     simple: bool = False        # also on Settings, Simple
     wizard: int = 0             # setup wizard step 1-6, 0 = not in the wizard
+    mirror: str = ""            # a choice also copied to this field, if offered
+    fills: str = ""             # a preset choice fills this field (uimodel)
 
     @property
     def text(self) -> str:
@@ -73,17 +75,20 @@ _MAINT = (("maintenance_enabled", "==", True),)
 _ONE = (("inverter_count", "==", 1),)
 _SEVERAL = (("inverter_count", ">", 1),)
 _PHASES = (("meter_phases", ">", 1),)
+# One inverter stored flat has no name or capacity (uimodel._roster_encode).
+_LISTED = (("inverter_shape", "!=", "flat"),)
 
 # The per-inverter card. Its keys are `inverters.<field>` in config.yaml.
 ROSTER_FIELDS = (
-    Field("inverters.name", TEXT, wizard=2),
+    Field("inverters.name", TEXT, show=_LISTED, wizard=2),
     Field("inverters.setpoint_entity", ENTITY, kind="number", wizard=2),
     Field("inverters.max_w", SLIDER, "W", step=100, wizard=2),
     Field("inverters.bms_soc_floor", SLIDER, "%", wizard=2),
     Field("inverters.soc_entity", ENTITY, kind="pct", wizard=2),
     Field("inverters.batt_entity", ENTITY, kind="power_w", wizard=2),
     Field("inverters.batt_invert", TOGGLE, wizard=2),
-    Field("inverters.capacity_kwh", NUMBER, "kWh", step=0.1, wizard=2),
+    Field("inverters.capacity_kwh", NUMBER, "kWh", step=0.1, show=_LISTED,
+          wizard=2),
 )
 
 GROUPS = (
@@ -123,7 +128,9 @@ GROUPS = (
     )),
     Group("tariff", (
         Part("", (
-            Field("ui.contract", SEGMENTED, wizard=4),
+            # A contract without a feed is also the price used when a feed
+            # is down, so the fallback follows it (uimodel._tariff_encode).
+            Field("ui.contract", SEGMENTED, wizard=4, mirror="ui.fallback"),
             Field("price_provider", SELECT, show=_DYNAMIC, wizard=4),
             Field("price_formula", TEXT,
                   show=_DYNAMIC + (("price_provider", "==", "custom_formula"),),
@@ -131,7 +138,8 @@ GROUPS = (
             Field("price_csv_path", TEXT,
                   show=_DYNAMIC + (("price_provider", "==", "manual_csv"),),
                   wizard=4),
-            Field("ui.region", SELECT, wizard=4),
+            Field("ui.region", SELECT, wizard=4,
+                  fills="price_taxes_eur_kwh"),
             Field("price_taxes_eur_kwh", NUMBER, "€/kWh", step=0.00001,
                   wizard=4),
             Field("price_markup_eur_kwh", NUMBER, "€/kWh", step=0.001,