feat: add price data management infrastructure (WIP)

Phase 1 of v0.3.0 date range and on-demand download implementation.

Database changes:
- Add price_data table (OHLCV data, replaces merged.jsonl)
- Add price_data_coverage table (track downloaded date ranges)
- Add simulation_runs table (soft delete support)
- Add simulation_run_id to positions table
- Add comprehensive indexes for new tables

New modules:
- api/price_data_manager.py - Priority-based download manager
  - Coverage gap detection
  - Smart download prioritization (maximize date completion)
  - Rate limit handling with retry logic
  - Alpha Vantage integration

Configuration:
- configs/nasdaq100_symbols.json - NASDAQ 100 constituent list

Next steps (not yet implemented):
- Migration script for merged.jsonl -> price_data
- Update API models (start_date/end_date)
- Update tools/price_tools.py to read from database
- Simulation run tracking implementation
- API integration
- Tests and documentation

This is work in progress for the v0.3.0 release.

configs/nasdaq100_symbols.json

@@ -0,0 +1,18 @@
+{
+  "symbols": [
+    "NVDA", "MSFT", "AAPL", "GOOG", "GOOGL", "AMZN", "META", "AVGO", "TSLA",
+    "NFLX", "PLTR", "COST", "ASML", "AMD", "CSCO", "AZN", "TMUS", "MU", "LIN",
+    "PEP", "SHOP", "APP", "INTU", "AMAT", "LRCX", "PDD", "QCOM", "ARM", "INTC",
+    "BKNG", "AMGN", "TXN", "ISRG", "GILD", "KLAC", "PANW", "ADBE", "HON",
+    "CRWD", "CEG", "ADI", "ADP", "DASH", "CMCSA", "VRTX", "MELI", "SBUX",
+    "CDNS", "ORLY", "SNPS", "MSTR", "MDLZ", "ABNB", "MRVL", "CTAS", "TRI",
+    "MAR", "MNST", "CSX", "ADSK", "PYPL", "FTNT", "AEP", "WDAY", "REGN", "ROP",
+    "NXPI", "DDOG", "AXON", "ROST", "IDXX", "EA", "PCAR", "FAST", "EXC", "TTWO",
+    "XEL", "ZS", "PAYX", "WBD", "BKR", "CPRT", "CCEP", "FANG", "TEAM", "CHTR",
+    "KDP", "MCHP", "GEHC", "VRSK", "CTSH", "CSGP", "KHC", "ODFL", "DXCM", "TTD",
+    "ON", "BIIB", "LULU", "CDW", "GFS", "QQQ"
+  ],
+  "description": "NASDAQ 100 constituent stocks plus QQQ ETF",
+  "last_updated": "2025-10-31",
+  "total_symbols": 101
+}