Add time display picker (Local/UTC/Server) and parameterize SQL

[erikdarlingdata]

Summary

• Time display picker on Query Store toolbar: switch between Local, UTC, and Server time
• All timestamps update live across the grid, time-range slicer, and history drill-down window
• Server UTC offset fetched on connect (DATEDIFF(MINUTE, GETUTCDATE(), GETDATE()))
• Parameterized hoursBack and daysBack in QueryStoreService SQL (previously string-interpolated)

Test plan

• Build: 0 errors
• Switch time modes — grid, slicer labels, and slicer X-axis all update
• History drill-down chart and grid respect the selected mode
• Server mode shows correct offset from UTC
• No crash on QS tab open (IsInitialized guard)

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

• New Features

  • Added time display mode selector allowing users to view query execution times in Local, UTC, or Server time zones.

• Improvements

  • Enhanced time formatting consistency across query result displays and history charts.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

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Review profile: CHILL

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Run ID: f8056b8f-80a1-41eb-b6a9-1b7a971ac730

📥 Commits

Reviewing files that changed from the base of the PR and between 94b36cc and 8699104.

📒 Files selected for processing (8)

• src/PlanViewer.App/Controls/QuerySessionControl.axaml.cs
• src/PlanViewer.App/Controls/QueryStoreGridControl.axaml
• src/PlanViewer.App/Controls/QueryStoreGridControl.axaml.cs
• src/PlanViewer.App/Controls/TimeRangeSlicerControl.axaml.cs
• src/PlanViewer.App/Dialogs/QueryStoreHistoryWindow.axaml.cs
• src/PlanViewer.Core/Models/QueryStoreHistoryRow.cs
• src/PlanViewer.Core/Services/QueryStoreService.cs
• src/PlanViewer.Core/Services/TimeDisplayHelper.cs

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📝 Walkthrough

Walkthrough

The PR introduces a time display mode selector allowing users to view timestamps in Local, UTC, or Server time zones. A new TimeDisplayHelper service centralizes timestamp conversion and formatting logic. A UI dropdown is added to QueryStoreGridControl, server UTC offset is fetched upon connection, and multiple display locations are updated to use the helper instead of inline conversions.

Changes

Cohort / File(s)	Summary
Time Display Helper & Core Service src/PlanViewer.Core/Services/TimeDisplayHelper.cs, src/PlanViewer.Core/Services/QueryStoreService.cs	New TimeDisplayHelper utility class with TimeDisplayMode enum and methods for converting/formatting timestamps. SQL queries in QueryStoreService updated to use parameterized queries for @hoursBack and @daysBack instead of string interpolation.
UI Time Display Selection src/PlanViewer.App/Controls/QueryStoreGridControl.axaml, src/PlanViewer.App/Controls/QueryStoreGridControl.axaml.cs	Added ComboBox dropdown ("Time display" toolbar) with Local/UTC/Server options. Handler refreshes grid, notifies rows of display mode change, and redraws time range slicer. QueryStoreRow.LastExecutedLocal now uses helper formatting; added NotifyTimeDisplayChanged() method.
Server Offset Fetching src/PlanViewer.App/Controls/QuerySessionControl.axaml.cs	New FetchServerUtcOffset() method executes SELECT DATEDIFF(MINUTE, GETUTCDATE(), GETDATE()) on successful connection and assigns result to TimeDisplayHelper.ServerUtcOffsetMinutes.
Time Display Conversions in Views src/PlanViewer.Core/Models/QueryStoreHistoryRow.cs, src/PlanViewer.App/Dialogs/QueryStoreHistoryWindow.axaml.cs	Replaced inline ToLocalTime() formatting with TimeDisplayHelper.FormatForDisplay() and ConvertForDisplay() calls for consistency.
Slicer Control Updates src/PlanViewer.App/Controls/TimeRangeSlicerControl.axaml.cs	Changed Redraw() visibility from private to public. Updated chart X-axis labels and selection range text to use TimeDisplayHelper.ConvertForDisplay() instead of direct ToLocalTime().

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• Add Query Store history drill-down with multi-plan charting #98: Modifies the same time-display conversion logic in QueryStoreHistoryWindow and QueryStoreHistoryRow, directly related to this PR's refactoring of inline time conversions.
• Feature/query store timeslicer #114: Touches QueryStoreGridControl and TimeRangeSlicerControl time-slicer integration; this PR adjusts parameterization in QueryStoreService.FetchTimeSliceDataAsync potentially introduced by that PR.
• v1.2.0 Release #100: Modifies QuerySessionControl and introduces time-display infrastructure in the same QueryStore/UI flow as this PR.

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• Commit unit tests in branch feature/time-display-picker

📝 Coding Plan

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