v0.2.0 — multi-protocol gateway

Multi-protocol gateway: OpenAI-compatible inbound facade (POST /v1/chat/completions) + Anthropic-native passthrough, reusable path->protocol classifiers, Router.Think/LongContext routing, config hot-reload, and access logging with secret redaction. All upstream test-port GAP skips closed (0 remaining); full suite green under -race incl. chaos/security/mutation/helixqa. See CHANGELOG.md.