fix: log only metadata for Live WebSocket diagnostics (#3865)

Aligns Live, forks, and sideband WebSocket diagnostics with the existing
SDK logging pattern: message sizes and generic connection and
queue-warning messages. Extends sync and async logging coverage.

Validation: 460 related tests passed, plus 84 logging tests with
Pydantic v1. Ruff, mypy, changed-file formatting, and wheel/sdist builds
pass.