Feature/query store timerange improvments

[rferraton]

What does this PR do?

Improve TimeSlicer

• box selector for time range selection : adapt the selected period
• tooltips for data and time in RangeTimeSlicer
• vertical bands to display days inside the RangeTimeSlicer (even with gaps)
• add a "move bar" at the top of the selected period
• allow to move RangeTimeSlicer period using keyboards arrows left and right

Which component(s) does this affect?

• Desktop App (PlanViewer.App)
• Core Library (PlanViewer.Core)
• CLI Tool (PlanViewer.Cli)
• SSMS Extension (PlanViewer.Ssms)
• Tests
• Documentation

How was this tested?

Describe the testing you've done. Include:

• Plan files tested : QueryStore
• Platforms tested : Windows Only

Checklist

• I have read the contributing guide
• My code builds with zero warnings (dotnet build -c Debug)
• All tests pass (dotnet test)
• I have not introduced any hardcoded credentials or server names

[erikdarlingdata]

Looks good — solid UX improvements to the time range slicer. A few minor nits (DispatcherTimer reuse, missing PointerExited for hover dot, Children[^1] pattern) but nothing blocking. Approving.