feat: AI/BI dashboard, country in gold layer, randomized seed data

[andre-salvati]

Summary

• Added `country` to `curated.order_enriched` and `report.order_agg` (and SDP equivalents) so the gold layer carries the full customer dimension; unit and integration tests updated.
• Added an AI/BI (Lakeview) dashboard with three line charts (total value by date × country/product/category), three KPI counters (total value, orders, customers), and a global filter page (date range, country, customer, product, category). Dashboard JSON and DAB resource are generated by `sdk_generate_template_job.py` at deploy time — both files are gitignored.
• Randomized seed data: `qty` (1–5) and `total_item` ($10–$200) now use `F.rand` with fixed seeds instead of hardcoded constants, so chart lines no longer overlap.
• Completed README documentation: added "Databricks Dashboards" to the Technologies section, dashboard screenshot block, and replaced the placeholder dashboard Features bullet with a full description of the charts and filter panel.

Migration note

First deploy requires dropping the stale-schema gold tables before re-running `job1`:
```sql
DROP TABLE IF EXISTS ``.`curated`.`order_enriched`;
DROP TABLE IF EXISTS ``.`report`.`order_agg`;
```

Test plan

• `make test` — 9 unit tests pass
• `make deploy env=dev` — bundle validates and dashboard deploys
• `make run env=dev` — integration job passes (setup → run + run_sdp → validate)
• Open deployed dashboard, confirm KPI counters update with date filter
• Confirm line charts show distinct (non-overlapping) lines across countries/products/categories

🤖 Generated with Claude Code