[ENHANCEMENT] timeserieschart: add per-query stack override

[SoWieMarkus]

Description

Adds a per-query stack override to the Time Series Chart plugin, allowing individual queries to opt in or out of stacking regardless of the global visual stack setting. This mirrors the behavior of Grafana/Plutono, where stacking can be controlled at the series level.

What changed:

• Added a stack?: bool field to QuerySettingsOptions in the model, CUE schema, and Go SDK
• Added a Stack Switch in the QuerySettingsEditor
• Updated getTimeSeries() in data-transform.ts to prefer the per-query stack flag over the global visual.stack === 'all' when set
• Moved getCommonTimeScale and getTimeSeriesValues imports from @perses-dev/components to @perses-dev/core (because not available in @perses-dev/components? Can revert that change ofc)

Open question:

The drawing order of stacked series depends on the order queries are defined. This could be relevant now since time series can overlap. But if they are not stacked it's the same. So just a thought. A dedicated zIndex field in QuerySettingsOptions could give explicit control over this - though it only matters at higher opacity values anyway.

Also in Grafana / Plutono the Stacking Option is a boolean. I didn't want to adjust that since that would be a breaking change, but might also be something to consider.

Screenshots

Query 1 excluded from stacking.

Query 1 included again in stacking.

Checklist

• Pull request has a descriptive title and context useful to a reviewer.
• Pull request title follows the [<catalog_entry>] <commit message> naming convention using one of the
  following catalog_entry values: FEATURE, ENHANCEMENT, BUGFIX, BREAKINGCHANGE, DOC,IGNORE.
• All commits have DCO signoffs.

UI Changes

• Changes that impact the UI include screenshots and/or screencasts of the relevant changes.
• Code follows the UI guidelines.

[Copilot]

Pull request overview

Adds a per-query stack?: boolean override to the Time Series Chart plugin so individual queries can opt in/out of stacking regardless of the global visual stacking setting, and wires this through the model + UI + series transformation logic.

Changes:

• Extends query settings (TS model, CUE schema, Go SDK) with stack?: boolean.
• Adds a Stack override control to the Query Settings editor.
• Updates series generation to prefer per-query stack override over global visual.stack.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
timeserieschart/src/VisualOptionsEditor.tsx	Minor adjustment in visual stack option update line.
timeserieschart/src/utils/data-transform.ts	Implements per-query stack override logic in getTimeSeries() and moves getCommonTimeScale import.
timeserieschart/src/TimeSeriesChartPanel.tsx	Moves getTimeSeriesValues import to @perses-dev/core.
timeserieschart/src/TimeSeriesChartBase.tsx	Moves getCommonTimeScale import to @perses-dev/core.
timeserieschart/src/time-series-chart-model.ts	Adds stack?: boolean to QuerySettingsOptions.
timeserieschart/src/QuerySettingsEditor.tsx	Adds Stack override UI (Switch) and plumbing for query settings updates.
timeserieschart/sdk/go/time-series.go	Adds stack field to Go SDK query settings struct.
timeserieschart/schemas/time-series.cue	Adds stack?: bool to the CUE schema.

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[ibakshay]

@SoWieMarkus, I can also confirm that the tooltip is not working anymore when it is stacked after your changes. I tested manually.

[SoWieMarkus]

Can you explain what exactly is not working anymore? I know there are issues with the tooltip when stacking is enabled, but that an issue that was there before my change.

[ibakshay]

Great job with the PR! I left some minor comments.

I also have a question.
How does your change will affect the existing "Stack Series - All | None" feature?

[SoWieMarkus]

I also have a question. How does your change will affect the existing "Stack Series - All | None" feature?

@ibakshay The short answer: it doesn't change it. The per-query stack is purely an overlay on top of the existing global setting:

Global visual.stack	Per-query stack	Result
'none' / unset	unset	not stacked (unchanged)
'none' / unset	true	stacked (override, all queries that have that are stacked)
'none' / unset	false	not stacked
'all'	unset	stacked (unchanged)
'all'	true	stacked
'all'	false	not stacked (override)

(I added test cases for that)

So any query that doesn't set the per-query stack continues to behave exactly as before. In theory you could change the stack option to a boolean like it is done in Grafana or Plutono, but I didn't want to change that because it would be a breaking change.

In theory you could further extend this feature by adding a stacking groups and then assign a query to one of this groups, but that is definitely out of scope for this PR though 😛