PRICE-02 round 2: require now, undo the test loosening, analyse ties

- TariffPlan.arbitrage(now=...) is required (keyword-only, no default); so are
  homeview.trade_verdict/refusal_key's now. Existing test calls pass one.
- test_arbitrage.py: no module-level decide wrapper. Fixtures that probed a
  one-day plan after its extremes now hold two days (as a site does); the
  flap day gets a unique cheapest and dearest hour; the replay breaks its
  ties without direction. The flap bound is <= 4 and the replay check is
  len(_trades) < 365 again. 228 checks pass on the old and the new code.
- test_price02.py part 6: ties (equal quarters, a real 15-minute day,
  alternating hourly prices) and the required now.
- Identity pins: the masked digest is only for the older-tree comparison;
  this tree's own digests are pinned with nothing hidden.
- DECISIONS: the tie analysis with numbers.

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

goodwe_controller/tools/opt11p3_identity.py

@@ -123,7 +123,10 @@ def _trade_words(text):
     plan now drops price periods that have ended, so a sale's "above the
     cheapest" figure is a different number once the first cheap period is
     over, and the sentences say "price period" where they said "hour". Both
-    maps are applied to both sides, so only those two things are hidden."""
+    maps are applied to both sides, so only those two things are hidden.
+
+    ONLY FOR COMPARING WITH A TREE OLDER THAN PRICE-02. A pin of this tree
+    itself uses `digest()`, with nothing hidden."""
     text = text.replace("this hour is neither the buy hour nor the sell hour",
                         "now is not the cheapest or the dearest price period")
     text = re.sub(r"[0-9]+\.[0-9]+ above the cheapest",