Add pivot retest + engulfing strategy with dual take-profit

New strategy (pivot_retest_engulfing) that enters long/short trades at
pivot level retests confirmed by SMA 50 alignment and engulfing candle
patterns. Uses ATR-based stop loss with two take-profit levels — at TP1
half the position closes and SL moves to breakeven, at TP2 the rest closes.

- data_engine: add detect_engulfing() for bullish/bearish pattern detection
- backtester: add generate_signals_pivot_retest(), run_backtest_dual_tp(),
  update signal dispatcher and metrics for dual-TP trade format
- order_executor: support signal=-1 (SHORT), attach SL/TP levels
- config: switch to pivot_retest_engulfing with default params
- chart_trades: new mplfinance script to visualize entries on candlesticks
- README: rewrite with full setup guide, project structure, strategy docs
- requirements.txt: make portable (remove conda file:// paths), add mplfinance
- .env.example: add template for secrets

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

.claude/settings.local.json

@@ -8,7 +8,16 @@
       "Bash(python:*)",
       "Bash(git add:*)",
       "Bash(git commit:*)",
-      "Bash(git push:*)"
+      "Bash(git push:*)",
+      "Bash(git -C /c/Users/brent/Documents/Projects/fx-quant log --oneline -10)",
+      "Bash(where:*)",
+      "Bash(docker build:*)",
+      "Bash(docker-compose build:*)",
+      "Bash(docker-compose up:*)",
+      "Bash(docker-compose down:*)",
+      "Bash(docker-compose logs:*)",
+      "Bash(echo:*)",
+      "Bash(docker exec:*)"
     ]
   }
 }