fix: weekend-aware cycle — IVGate, pandas MultiIndex, ticker aliases, day/session in AI prompt

- auto_cycle.py: detect weekend/market session, build cycle_meta with day_of_week/is_weekend/market_note;
  IVGate skips iv_rank>=99 on weekends to avoid artificial weekend option premium cascade;
  inject portfolio context (open trades + price moves + concentration) before AI scoring;
  pass portfolio_context_block + run_id to both AI scorer and suggester
- ai_analyzer.py: _build_temporal_news_block injects market session banner (WEEKEND warning,
  pre/after-market note, or open session label) so AI knows markets are closed and defers execution to Monday
- iv_engine.py: add WHEAT/EUR/USD ticker aliases; skip saving IV snapshots on weekends to protect history;
  resolve aliases before slash-format conversion in _resolve_ticker
- technical_indicators.py: fix pandas MultiIndex from yfinance>=0.2 (droplevel+squeeze);
  use period proportional to lookback instead of fixed period=1d
- database.py: asset_class ticker-based fallback (_asset_class_from_ticker); one-time backfill migration
  for all NULL asset_class rows; ai_call_logs table + save/get helpers; normalize_ticker public function

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/services/auto_cycle.py

@@ -230,12 +230,41 @@ def run_cycle_once(trigger: str = "auto") -> Dict[str, Any]:
         else:
             _calib_label = f"Long terme ({_delta_minutes/60:.0f}h) — marchés ont eu le temps d'intégrer"
 
+        # ── Market calendar context ────────────────────────────────────────
+        from datetime import timezone as _tz
+        _now_utc = _now.replace(tzinfo=_tz.utc) if _now.tzinfo is None else _now.astimezone(_tz.utc)
+        _weekday = _now_utc.weekday()  # 0=Mon … 6=Sun
+        _day_names = ["Lundi", "Mardi", "Mercredi", "Jeudi", "Vendredi", "Samedi", "Dimanche"]
+        _is_weekend = _weekday >= 5
+        # CME equity/energy/metals futures: closed Fri 17:00 ET → Sun 18:00 ET
+        # Rough ET offset (UTC-5 winter / UTC-4 summer) — good enough for intent
+        _et_hour = (_now_utc.hour - 5) % 24
+        if _is_weekend:
+            _market_session = "closed"
+            _market_note = f"{_day_names[_weekday]} — marchés US et CME fermés. Derniers prix disponibles: vendredi clôture."
+        elif _et_hour < 4:
+            _market_session = "overnight"
+            _market_note = "Nuit US (overnight) — liquidité réduite, spreads larges."
+        elif _et_hour < 9:
+            _market_session = "pre_market"
+            _market_note = "Pré-marché US — prix indicatifs, faible liquidité."
+        elif _et_hour < 16:
+            _market_session = "open"
+            _market_note = "Marché US ouvert."
+        else:
+            _market_session = "after_hours"
+            _market_note = "After-hours US — prix indicatifs, liquidité réduite."
+
         cycle_meta = {
             "current_cycle_ts": _now.isoformat(),
             "last_cycle_ts": _last_cycle_ts_str,
             "delta_minutes": round(_delta_minutes, 1),
             "interval_hours": _interval_hours,
             "calibration_label": _calib_label,
+            "day_of_week": _day_names[_weekday],
+            "is_weekend": _is_weekend,
+            "market_session": _market_session,
+            "market_note": _market_note,
         }
         logger.info(
             f"[Cycle {run_id[:16]}] Cycle meta: delta={_delta_minutes:.0f}min depuis dernier cycle"
@@ -1075,6 +1104,10 @@ def _apply_iv_gate(
     except Exception:
         pass
 
+    # Detect weekend: IVR=100 on weekends is artificial (weekend premium) — ignore rank
+    from datetime import datetime as _dt_cls
+    _weekend_now = _dt_cls.utcnow().weekday() >= 5
+
     all_blocked: List[Dict] = []
 
     for sp in scored:
@@ -1093,6 +1126,11 @@ def _apply_iv_gate(
                 continue
 
             iv_rank = snap.get("iv_rank")
+            # On weekends, ATM IV is inflated by weekend premium (market makers can't hedge).
+            # IVR=99-100 on a weekend is almost always artificial — don't block on it.
+            if _weekend_now and iv_rank is not None and iv_rank >= 99.0:
+                iv_rank = None
+                snap = {**snap, "iv_rank": None}
             iv_current_pct = snap.get("iv_current_pct")
             iv_min_52w = snap.get("iv_min_52w_pct")
             iv_max_52w = snap.get("iv_max_52w_pct")