docs(BT-003B): record completed drilldown validation

docs/roadmap/done/BT-003B-event-comparison-drilldown.yaml

@@ -0,0 +1,17 @@
+id: BT-003B
+title: Event Comparison Drilldown
+status: done
+priority: P1
+effort: M
+depends_on:
+  - BT-003A
+tags:
+  - backtesting
+  - ui
+summary: The event comparison page now explains why one ranked strategy beat another by exposing a selectable drilldown over the ranked results.
+completed_notes:
+  - Added service-backed drilldown models in `app/services/event_comparison_ui.py` for ranked strategy selection, worst-LTV inspection, breach dates, and daily path rows.
+  - Updated `app/pages/event_comparison.py` to render a `Strategy drilldown` selector, selected-strategy summary cards, worst-LTV and breach-date highlights, and a daily path details table.
+  - Added regression coverage in `tests/test_event_comparison_ui.py` and extended `tests/test_e2e_playwright.py` so drilldown selection proves route-visible content changes.
+  - Local Docker validation is now confirmed on Docker Desktop: the stack starts cleanly, `/health` returns OK, and browser automation on the Docker-served `/{workspace_id}/event-comparison` route verified the drilldown UI and selection updates.
+  - The earlier Docker validation confusion was caused by a local SSH port-forward hijacking host requests to `localhost:8000`, not by the app container itself.