17 integration tests covering: - Happy path: token streaming, tool calls, multi-message sessions - Interrupt flow: approve and reject paths with manager tracking - Session TTL: expiration, sliding window reset, interrupt extension - Validation: invalid JSON, missing fields, size limits - Interrupt TTL: expired interrupt sends retry prompt Fills Phase 1 test gap for integration-level WebSocket coverage. Total: 170 tests, 92.15% coverage.