feat: trading bot MVP — ICT Order Block + Liquidity Sweep strategy

Full-stack trading bot with:
- FastAPI backend with ICT strategy (Order Block + Liquidity Sweep detection)
- Backtester engine with rolling window, spread simulation, and performance metrics
- Hybrid market data service (yfinance + TwelveData with rate limiting + SQLite cache)
- Simulated exchange for paper trading
- React/TypeScript frontend with TradingView lightweight-charts v5
- Live dashboard with candlestick chart, OHLC legend, trade markers
- Backtest page with configurable parameters, equity curve, and trade table
- WebSocket support for real-time updates
- Bot runner with asyncio loop for automated trading

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

backend/app/services/data_providers/constants.py

@@ -0,0 +1,82 @@
+"""
+Constantes de mapping entre les noms canoniques du projet
+et les symboles/intervalles propres à chaque source de données.
+"""
+
+# ── Limites yfinance (jours de données disponibles par granularité) ──────────
+YF_MAX_DAYS: dict[str, int] = {
+    "M1": 7,
+    "M5": 60,
+    "M15": 60,
+    "M30": 60,
+    "H1": 730,
+    "H4": 730,
+    "D": 9999,
+}
+
+# ── Durée d'une bougie en minutes ─────────────────────────────────────────────
+GRANULARITY_MINUTES: dict[str, int] = {
+    "M1": 1,
+    "M5": 5,
+    "M15": 15,
+    "M30": 30,
+    "H1": 60,
+    "H4": 240,
+    "D": 1440,
+}
+
+# ── Mapping vers les intervalles yfinance ─────────────────────────────────────
+GRANULARITY_TO_YF: dict[str, str] = {
+    "M1": "1m",
+    "M5": "5m",
+    "M15": "15m",
+    "M30": "30m",
+    "H1": "1h",
+    "H4": "4h",
+    "D": "1d",
+}
+
+# ── Mapping vers les intervalles TwelveData ───────────────────────────────────
+GRANULARITY_TO_TD: dict[str, str] = {
+    "M1": "1min",
+    "M5": "5min",
+    "M15": "15min",
+    "M30": "30min",
+    "H1": "1h",
+    "H4": "4h",
+    "D": "1day",
+}
+
+# ── Mapping instrument → symbole yfinance ─────────────────────────────────────
+INSTRUMENT_TO_YF: dict[str, str] = {
+    "EUR_USD":    "EURUSD=X",
+    "GBP_USD":    "GBPUSD=X",
+    "USD_JPY":    "USDJPY=X",
+    "USD_CHF":    "USDCHF=X",
+    "AUD_USD":    "AUDUSD=X",
+    "USD_CAD":    "USDCAD=X",
+    "GBP_JPY":    "GBPJPY=X",
+    "EUR_JPY":    "EURJPY=X",
+    "EUR_GBP":    "EURGBP=X",
+    "SPX500_USD": "^GSPC",
+    "NAS100_USD": "^NDX",
+    "XAU_USD":    "GC=F",
+    "US30_USD":   "YM=F",
+}
+
+# ── Mapping instrument → symbole TwelveData ───────────────────────────────────
+INSTRUMENT_TO_TD: dict[str, str] = {
+    "EUR_USD":    "EUR/USD",
+    "GBP_USD":    "GBP/USD",
+    "USD_JPY":    "USD/JPY",
+    "USD_CHF":    "USD/CHF",
+    "AUD_USD":    "AUD/USD",
+    "USD_CAD":    "USD/CAD",
+    "GBP_JPY":    "GBP/JPY",
+    "EUR_JPY":    "EUR/JPY",
+    "EUR_GBP":    "EUR/GBP",
+    "SPX500_USD": "SPY",
+    "NAS100_USD": "QQQ",
+    "XAU_USD":    "XAU/USD",
+    "US30_USD":   "DJI",
+}