feat: multi-strategy paper trader — N strategie in parallelo su testnet

- src/live/multi_runner.py: orchestratore con fetch raggruppato per asset/tf
- src/live/strategy_worker.py: worker indipendente con stato persistente JSONL
- src/live/strategy_loader.py: import dinamico classi Strategy
- strategies.yml: config dichiarativa con defaults e override per strategia
- Docker: container unico, strategies.yml montato come volume read-only
- Supporta hot-add: aggiungi riga YAML + restart, storico intatto
- Ogni strategia: €1000 USDC virtuale, equity tracking, Telegram notify

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -1,16 +1,17 @@
 services:
   paper-trader:
     build: .
-    container_name: pythagoras-paper
+    container_name: pythagoras-multi
     restart: unless-stopped
     volumes:
       - ./data:/app/data
+      - ./strategies.yml:/app/strategies.yml:ro
     env_file:
       - .env
     environment:
       - PYTHONUNBUFFERED=1
     healthcheck:
-      test: ["CMD", "python", "-c", "import json; s=json.load(open('/app/data/paper_trades/status.json')); assert s['last_update']"]
+      test: ["CMD", "python", "-c", "import os; assert any(f.endswith('status.json') for r,d,fs in os.walk('/app/data/paper_trades') for f in fs)"]
       interval: 120s
       timeout: 10s
       retries: 3