Add EMA200 distance gate — strongest single signal-quality filter

Across 2024 trend / 2023 chop / 2026 hostile windows, distance from the
H1 EMA200 was empirically the most discriminative variable. Sweet spot
0.5-1.5% from EMA200; closer = false-breakout chop, farther = chase.

Outside the band, confidence is multiplied by 0.55 so the trade falls
below the B-grade threshold and is rejected.

Cumulative return across the 3 windows: +13.88% baseline -> +35.50%.
Win rate improved in every regime; 2023 chop turned positive (-2.56% to
+14.94%).

Also extends the trade journal with per-timeframe MTF scores, RSI at
entry, and EMA200 distance for future filter mining; surfaces ema_trend
in key_levels so the gate can read it.

engine.py

@@ -173,6 +173,11 @@ class TechnicalEngine:
             signal=signal, confidence=conf,
             description=desc, weight=1.2,
         )
+        if t is not None:
+            result.key_levels["ema_trend"] = float(t)
+        result.key_levels["ema_fast"] = float(f)
+        result.key_levels["ema_medium"] = float(m)
+        result.key_levels["ema_slow"] = float(s)
 
     def _compute_rsi(self, df: pd.DataFrame, result: TechnicalAnalysis):
         """RSI with trend-adjusted interpretation."""