Realtime breakdown and timeseries APIs

We shipped first-class realtime endpoints to drive live operational dashboards alongside the existing historical metrics APIs.

• Added RealTime Timeseries and RealTime Breakdown endpoints under views with sub-minute resolution.
• Realtime timeseries now uses 5-second buckets for smooth graphs and applies a gap-filling strategy so the curve never goes flat during quiet periods.
• Breakdown values are returned sorted in descending order so the largest contributors appear first by default.
• Improves graph alignment and consistency between the breakdown and timeseries panels.