Create dashboard from YAML

Create a new dashboard from YAML definition. Use this to create visualization dashboards for spans, events, logs, and metrics. Supports grid-based and table-based layouts with PromQL-style metric queries. The YAML body must include: schema (v2 or v3) and name. Optional fields: version, tags. Use get_dashboard_yaml on an existing dashboard to see the exact YAML format before creating. The API strictly rejects unknown fields. Table and table_grid_items overrides use column (required, must match a query alias) + properties (array of {name, value}). Grid item overrides (in grid_rows) use matchers + properties (array of {name, value}). Sparkline is a table column property ({name: sparkline, value: true}), not a top-level field. Documentation: https://uptrace.dev/features/dashboards