PRICE-01 round 3: replace the fixed-tariff notification with a log line and a settings note

G1: remove the false 'Fixed tariff not used' notification. One INFO line at
start and an info note beside the setting (EN/NL) when price_service has a
non-blank static_profile; the old notification id is dismissed at start.
DOCS, migration step 5 and DECISIONS rule 7 now say what the code does.
S05: whitespace-only static_profile counts as not set.
G2: maintenance_enabled read through MaintConfig.from_options().

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

goodwe_controller/app/validate.py

@@ -1659,6 +1659,12 @@ def _price_problems(opts: dict, notes: list | None = None) -> list[str]:
                 f"{S('static_profile')} is empty, so the site has no tariff "
                 "at all while the price feed is down.")
 
+    # PRICE-01: not a fault, so an info note and no log line here (the add-on
+    # logs it once at start). With `price_service` the fixed tariff is only the
+    # plan's last fallback; the cheap window and the gate do not read it.
+    if pid == "price_service" and str(opts.get("static_profile", "") or "").strip():
+        _advise(notes, "info", ("static_profile",), messages.FIXED_TARIFF_NOTE)
+
     # ⚠️ OPT-04. THE THREE WAYS `arbitrage_enabled: true` CAN BE A LIE, refused
     # rather than logged, because a strategy that is armed in the UI and cannot
     # fire is indistinguishable from one that fires and finds no opportunity -