Previously only Claude and Codex had log-scanning-level token usage
reporting (Flow B). This adds scanners for the remaining three runtimes:
- OpenCode: reads JSON message files from ~/.local/share/opencode/storage/message/
- OpenClaw: reads JSONL session files from ~/.openclaw/agents/*/sessions/
- Hermes: reads JSONL session files from ~/.hermes/sessions/
All three are registered in Scanner.Scan() and follow the same
(date, provider, model) aggregation pattern as existing scanners.
