EUR: document closure of calendar + H1-hybrid avenues

Surprise-conditioned entries lose 2-5p at every horizon both years;
avoidance filter marginal for EUR and profit-removing for XAU; the
H1-direction + M15-pullback prototype failed its pre-registered kill
criteria (2024-25 OOS negative). EUR stays informational-only.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pair_signals/eurusd.py

@@ -37,9 +37,20 @@ survives because gold's ATR/spread ratio is several times larger.
 EUR/USD therefore ships FUNCTIONAL BUT OFF by default: it is not in
 PlatformConfig.scan_pairs. Scan it on demand (main.py --pair EURUSD,
 or add to scan_pairs) but treat all EUR M5/M15 signals as informational
-only. Open avenues needing new data/infra: calendar-anchored entries
+only.
-(requires a historical Forex Factory archive), limit-entry cost
+
-reduction (needs tick data to model fills honestly), H4/D1 swing.
+Calendar + hybrid avenues CLOSED 2026-07-12 (see backtest/research/):
+  - Surprise-conditioned entries (real Forex Factory archive, verified
+    timestamps): follow-surprise loses 2-5 pips at every horizon in
+    both years under every conditioning. The market prices the
+    surprise within the release bar.
+  - Event-window avoidance: EUR effect marginal/inconsistent (and on
+    XAU it would REMOVE profit — event-window trades outperform).
+  - H1-anchored direction + M15 pullback execution (pre-registered
+    kill criteria): 2025-26 +2.8R PF 1.11, 2024-25 OOS -1.5R PF 0.92
+    -> killed.
+Remaining avenues need data we don't have: tick-level fills for
+limit-entry cost reduction, or H4/D1 swing horizons.
 """
 
 from typing import Optional, List