CORRECTED: Data Provider Hierarchy — Schwab FIRST for ALL

Henry corrected the data provider hierarchy. Schwab is PRIMARY for ALL data types (daily AND intraday), not just daily. Correct order: 1. Schwab (primary, if authenticated) 2. Alpaca (secondary fallback) 3. yfinance (last resort). Updated data_provider.py to route ALL resolutions through Schwab first, including 1m, 5m, 15m, 1h. Schwab maps: 1m→frequency=1, 5m→frequency=5, 15m→frequency=15, 1h→frequency=30. Period sizes auto-calculated. Previous memory (Schwab=daily, Alpaca=intraday) was WRONG.