Add Black-Litterman, AI views, sentiment regime, and DeFi yield strat…

…egies

- Black-Litterman model with AI-generated views (Claude, OpenAI, Perplexity)
- AI middleware with provider adapters and lazy SDK imports
- Prompt templates using 6-layer engineering pattern
- Sentiment-enhanced regime detection (Fear & Greed, funding rates, exchange flows)
- DeFi yield-adjusted optimization via DeFiLlama
- 3 new strategies: black-litterman, sentiment-regime, yield-adjusted
- 159 tests passing, all lint clean

Use absolute image URLs for PyPI rendering

Add PyPI publishing, CI workflows, and package rename to orbiter-crypto