UX-13 P4 review fixes (PR #146, comment 1887)

R1: first_start also needs a Store created at this boot (Store.fresh), so
    old never-started sites (both TEST-23 add-ons, one in shadow) stay on Home.
R2: a kettle skip after a fall says on the last step that the reading went down.
R3: the shadow switch goes only on the model the wizard posts, never into V.
R4: Home Assistant not answering is red on the last step.
R5: meter + solar + battery below -300 W flags a reversed battery sensor.
R6: the live checks say what to change and where.

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

goodwe_controller/app/store.py

@@ -585,6 +585,9 @@ class Store:
     def __init__(self, path: str = "/data/state.json"):
         self.path = path
         self.data = dict(DEFAULTS)
+        # UX-13 P4: True when this boot found no state file, i.e. a new /data.
+        # Only the setup wizard's first-run rule reads it (uipage.setup_needed).
+        self.fresh = False
         self.load()
 
     def load(self) -> None:
@@ -598,6 +601,7 @@ class Store:
                           self.data.get("phase"), self.data.get("last_completed"),
                           self.data.get("sign_tripped"))
         except FileNotFoundError:
+            self.fresh = True
             _LOG.info("no saved state, starting fresh")
         except (json.JSONDecodeError, OSError) as err:
             # A corrupt state file must not stop the controller: losing the