feat: add live import progress tracking with job store
- Add jobStore.js: in-memory job store with rich job objects (liveStats,
logs, errors, cancellation, timing, success rate)
- Rewrite manageProducts.js: structured logging ([STATS], [PRODUCT-OK],
[PRODUCT-FAIL], [SKIP], [FETCH], [CANCEL], etc.), per-product cancel
checks, jobStore integration
- server.js: expose GET /health, GET /jobs, GET /jobs/:id,
POST /jobs/:id/cancel, GET /shops endpoints
- tokenStore.js: add listTokens() export
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>