Tune 5M signals, fix XAU regression, add signal dedup cooldown

EUR/USD 5M: raise min_entry_score 28→35, block hours 4/19/21
  → 83.4% WR, 145 trades, +9.68R, PF 1.42 (120-day)

XAU/USD 5M: fix B-grade exclusion regression in setup_grades,
  add breakeven trail (trigger 0.15R, buffer 0.05R)
  → 84.9% WR, 4810 trades, +164.54R, PF 1.23 (730-day)

EUR/USD M15: tighten defaults (SL 1.5x ATR, TP 1.0x, min_rr 0.5,
  block ranging+transitioning, BE trigger 0.2R)

Backtest: multiprocess fork parallelism, vectorized pre-filter,
  CUDA preload fix, per-pair BE trigger routing

Telegram bot: add signal deduplication — suppress repeated
  same-direction messages within 5-bar cooldown per pair+TF.
  Resend on direction flip, quality upgrade, or cooldown expiry.
  Manual scans always ungated.

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

signal_aggregator.py

@@ -498,7 +498,8 @@ class SignalAggregator:
                    if report.primary_analysis else 0)
             if atr > 0:
                 report.trade_setup = self._generate_xau_atr_trade_setup(report, atr)
-        if report.trade_setup is None and report.signal_quality in ("A+", "A", "B", "C"):
+        setup_grades = ("A+", "A", "B", "C")
+        if report.trade_setup is None and report.signal_quality in setup_grades:
             report.trade_setup = self._generate_trade_setup(report, pip_value)
 
         # ── 8. Reasons ─────────────────────────────────────────────