Introduces STRATEGY_REGISTRY, alpha_shield_allocation(), and compute_weights()
in strategy.py. Updates runner.py to dynamically load equity symbol, gold
symbol, and SMA window from the registry based on strategy_name, enabling
Alpha Shield (JUNIORBEES.NS + GOLDBEES.NS, 60M SMA) alongside Golden Nifty.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>