feat: expose deep analysis llm metrics

[okJiang]

Summary

• add worker-side deep analysis token/request counters for chunk_analysis and global_synthesis
• expose the counters on the worker health server at /metrics
• record metrics directly from Qwen deep analysis results without changing report behavior

Validation

• corepack pnpm -r --workspace-concurrency=1 typecheck
• corepack pnpm test -- --runInBand apps/worker/src/qwen-deep-analysis.service.spec.ts
• corepack pnpm test -- --runInBand apps/worker/src/deep-analysis-report-processor.service.spec.ts

Notes

• this PR covers the mem9-node half of the first benchmark accounting loop