Reference plan only - no code changes. Describes the BaseLLMClient
refactor, AnthropicClient on the official SDK, per-consumer routing via
a config.json "llm" block, tests, commit sequence, and effort estimate
for the day we route the agent panel to Claude while news stays on
DeepSeek.
Claude-Session: https://claude.ai/code/session_01SisdfkxnXNL9iZsXxN3T15
Harwinder Sekhon