feat: live trading, multi-pair backtest, README, CI workflow

- Add live trading loop (live.rs) with MT5 pending order placement,
  state persistence, and per-symbol tokio task for multi-pair
- Extract backtest engine to backtest.rs and shared helpers to helpers.rs
- Multi-pair support via SYMBOLS env var (comma-separated)
- Add GitHub Actions workflow: Linux musl + Windows release binaries
- Add README with strategy docs, config reference, backtest results
- Clean up warnings, remove unused env vars, tighten .gitignore

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

.env.example

@@ -2,40 +2,41 @@
 MT5_BASE_URL=http://localhost:8080
 
 # ── Symbol & Timeframe ──────────────────────────────────────────────────────
-# XAUUSDm: flagship (PF=1.47, +21606% over 18m)
-# XAGUSDm: best risk-adjusted (PF=1.63, Max DD only -$192)
-# BTCUSDm: viable (PF=1.25), USOILm: viable (PF=1.32)
-# EURUSDm/GBPUSDm: negative edge — not recommended
+# Single pair:
 SYMBOL=XAUUSDm
+# Multi pair (comma-sep, overrides SYMBOL):
+# SYMBOLS=XAUUSDm,XAGUSDm
 TIMEFRAME=M5
 
+# ── Risk ─────────────────────────────────────────────────────────────────────
+RISK_PCT=0.01
+
+# ── Momentum Candle Thresholds ───────────────────────────────────────────────
+BODY_PCT_MIN=0.5
+CLOSE_PCT_MIN=0.8
+
+# ── FVG Setup ────────────────────────────────────────────────────────────────
+FVG_EXPIRY_CANDLES=10
+MIN_FVG_PIPS=1
+MIN_SL_PIPS=5
+SL_BUFFER=0
+MIN_RR=1.5
+# TIMEOUT_CANDLES=0
+
+# ── Friction ─────────────────────────────────────────────────────────────────
+COMMISSION_PER_LOT=7
+SLIPPAGE_POINTS=2
+SPREAD_OVERRIDE=0
+
+# ── EMA Trend Filter ─────────────────────────────────────────────────────────
+EMA_PERIOD=20
+
 # ── Backtest ─────────────────────────────────────────────────────────────────
 BACKTEST_BALANCE=600
-BACKTEST_CANDLES=99000
+BACKTEST_CANDLES=50000
 # DATE_FROM=2025-01-01
 # DATE_TO=2025-12-31
 
-# ── Risk ─────────────────────────────────────────────────────────────────────
-RISK_PCT=0.01             # risk per trade (0.01 = 1%)
-
-# ── Momentum Candle Thresholds ───────────────────────────────────────────────
-BODY_PCT_MIN=0.5          # minimum body/range ratio — 0.50 optimal (PF 1.47 vs 1.43 at 0.60)
-CLOSE_PCT_MIN=0.8         # close must be in top/bottom 20% of range
-
-# ── FVG Setup ────────────────────────────────────────────────────────────────
-FVG_EXPIRY_CANDLES=10     # invalidate setup after N candles without fill
-MIN_FVG_PIPS=1            # minimum FVG zone width in pips (rejects non-gap patterns)
-MIN_SL_PIPS=5             # minimum SL distance in pips (rejects degenerate setups)
-SL_BUFFER=0               # extra buffer beyond impulse candle extreme for SL
-MIN_RR=1.5                # minimum reward:risk ratio
-TIMEOUT_CANDLES=0         # force close after N candles (0 = disabled)
-
-# ── Friction ─────────────────────────────────────────────────────────────────
-COMMISSION_PER_LOT=7      # round-trip commission in USD
-SLIPPAGE_POINTS=5         # extra SL slippage in MT5 points
-SPREAD_OVERRIDE=0         # override spread (0 = Zero/Raw account)
-
-# ── EMA Trend Filter ─────────────────────────────────────────────────────────
-# Critical: without EMA filter strategy loses money on XAU
-# EMA20 is recommended (EMA10 overfits, EMA50 reduces returns significantly)
-EMA_PERIOD=20
+# ── Live Trading ─────────────────────────────────────────────────────────────
+# LIVE=true
+# LIVE_POLL_SECS=30