feat(paykit): add plan drift detection with hash-based sync check

- Compute SHA-256 hash per plan at normalization time, store in DB at push
- Check hash in subscribe() to catch out-of-sync plans at runtime (500)
- Add dev-mode init check via lazy context in createPayKit
- Replace `status` CLI command with `check` (exits non-zero on drift)
- Refactor product fetching: remove getLatestProductWithPrice, add withProviderInfo
- Use planMap for O(1) lookups instead of array.find
- Fix pretty logs in all dev environments (remove isTTY dependency)
- Make context initialization fully lazy (no eager start at module load)