SAFETY-90 review: count the start-up seconds like a gap

While the add-on is down the batteries are at 0 W (it sets 0 W when it
stops; the ESP32 watchdog after 30 s), so the import before its first
reading was the house, not the aim. Those seconds now count at
gap_w(limit, the import seen first), and after a restart the restored
reading's held 30 s is topped up the same way. Status row: "counted as
high use". Tests take the pre-start import as the house (batteries at
0 W) and add restarts of 10/60/150 s with a restored averager.

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

goodwe_controller/app/messages.py

@@ -794,9 +794,9 @@ def row_peak_guard_blind(why: str) -> str:
 
 
 def row_peak_guard_unmeasured() -> str:
-    """SAFETY-90. Before the first reading; that part counts as on target."""
+    """SAFETY-90. Before the first reading; that part counts as high use."""
     return ("Peak guard: part of this 15-minute period was not measured, "
-            "counted as on target")
+            "counted as high use")
 
 
 def row_peak_guard_on(floor_w, limit_w, *, shadow: bool = False) -> str: