Two defects fixed:
- ensure_banner_chart created an orphan 'Maintenance Banner' markdown chart
(polluted Charts menu and dashboard exports). The banner is now a native
MARKDOWN element in position_json; chart_id is a synthetic layout key.
- insert_banner_markdown_at_top blindly targeted GRID_ID; on ROOT->TABS
dashboards (FI-0085) GRID_ID is orphaned and the banner never rendered.
The layout is now normalized to ROOT->GRID_ID->[ROW-banner, ...] with
recursive parents update, matching the proven-working manual example.
Review-driven hardening:
- liveness check verifies reachability from ROOT (children graph), so
dashboards corrupted by the old bug self-heal on the next start.
- insert removes stale ROW-banner-*/MARKDOWN-banner-* keys (single banner).
- decision memory (@RATIONALE/@REJECTED) added to both modules.
- new ops script scripts/cleanup_maintenance_banner_charts.py (dry-run by
default) deletes already-created bogus banner charts in prod.
busya
80dad15458