OPT-15: price-run fixes (quarter edge, charge-end overshoot, refusal probe)

F1: with battery modes on, the peak guard projects the quarter `now` is in
even before its first P1 sample (PeakTracker.project(roll=True)), and only
a measured stop latches the period. The edge tick no longer reads "no
seconds left", so a charge is not stopped and latched at a quarter edge.

F2: after a run edge the loop is held at E until the meter shows the step
(EDGE_HOLD_S, longer while the battery still moves). The replay gained a
lag model (dead time, reading age, P1 debounce, 1 s cycles) that shows
TEST-23's overshoot without the hold.

F3: a charge refuser's SAFETY-73 probe inside a cheap run is a charger
pinned at PROBE_W, the others rest, so the probe actually runs.

Modes off stays byte-identical to 5a4cdc2 (new late-P1 identity scenarios).

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

goodwe_controller/app/p1.py

@@ -312,6 +312,12 @@ class QuarterAverager:
         """
         return self._last_net
 
+    @property
+    def held_t(self) -> float | None:
+        """Epoch seconds of the held sample. OPT-15: `PeakTracker.project()`
+        with `roll=True` credits it into the next block as `add()` will."""
+        return self._last_t
+
     @property
     def offtake_avg_w(self) -> float:
         """Average offtake over the part of the open block seen so far."""