Phase 3: MCP HTTP clients + Dockerization

Wrapper async tipizzati sui sei servizi MCP HTTP che Cerbero Bite
consuma in autonomia. 277 test pass, copertura clients 93%, mypy
strict pulito, ruff clean.

Base layer:
- clients/_base.py: HttpToolClient con httpx + tenacity (retry
  esponenziale 3x, timeout 8s, mapping HTTP→eccezioni tipizzate).
- clients/_exceptions.py: McpAuthError, McpServerError, McpToolError,
  McpDataAnomalyError, McpNotFoundError, McpTimeoutError.
- config/mcp_endpoints.py: risoluzione URL via Docker DNS
  (mcp-deribit:9011, ...) con override per servizio via env var;
  caricamento bearer token da secrets/core.token o
  CERBERO_BITE_CORE_TOKEN_FILE.

Wrapper:
- clients/macro.py: next_high_severity_within() per filtro entry §2.5.
- clients/sentiment.py: funding_cross_median_annualized() con
  annualizzazione per period nativo per exchange (Binance/Bybit/OKX
  1095, Hyperliquid 8760).
- clients/hyperliquid.py: funding_rate_annualized() per filtro §2.6.
- clients/portfolio.py: total_equity_eur(), asset_pct_of_portfolio()
  per sizing engine + filtro §2.7.
- clients/telegram.py: notify-only (no callback queue, no
  conferme — Bite auto-execute).
- clients/deribit.py: environment_info, index_price_eth,
  latest_dvol, options_chain, get_tickers, orderbook_depth_top3,
  get_account_summary, get_positions, place_combo_order (combo
  atomico), cancel_order.

CLI:
- cerbero-bite ping: health-check parallelo di tutti gli MCP con
  tabella rich (OK/FAIL/SKIPPED).

Docker:
- Dockerfile multi-stage Python 3.13 + uv, user non-root.
- docker-compose.yml con rete external "cerbero-suite", secret
  core_token montato a /run/secrets/core_token, env per ogni MCP.
- secrets/README.md documenta il setup del token.

Documentazione di intervento:
- docs/12-mcp-deribit-changes.md: spec delle modifiche apportate
  al server mcp-deribit (place_combo_order + override testnet via
  DERIBIT_TESTNET).

Dipendenze:
- aggiunto pytest-httpx per i test HTTP.
- rimosso mcp>=1.0 (non usiamo l'SDK MCP, parliamo via HTTP REST).

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

.gitignore

@@ -43,3 +43,6 @@ data/
 .env
 .env.*
 !.env.example
+secrets/*
+!secrets/.gitkeep
+!secrets/README.md