Sync ChartDetailView state with external valueElements updates

[vivekjyani]

Context / Spec

NO-2078 — ChartDetailView could get out of sync when chart updates were applied externally (change API, mirrored field updates, reset/recompute flows). The view initialized local @State once and then did not reliably re-sync both value elements and axis coordinates from model updates.

What Changed

1) ChartDetailView now syncs both chart values and chart coordinates from model updates

File: Sources/JoyfillUI/View/Fields/ChartView/ChartDetailView.swift

• Updated initial chartCoordinatesData source to read from chartDataModel.chartCoordinates.
• Added .onChange sync for chartDataModel.valueElements -> local valueElements.
• Added .onChange sync for chartDataModel.chartCoordinates -> local chartCoordinatesData.
• Both sync paths guard against redundant assignments.

2) External change payload now applies chart axis data through DocumentEditor

Files:

• Sources/JoyfillUI/ViewModels/DocumentEditor.swift

• Sources/JoyfillUI/ViewModels/DocumentEditor+Formulas.swift

• In parseChanges, axis values (xTitle, yTitle, xMin, xMax, yMin, yMax) are read from the incoming change payload and assembled into ChartData.

• updateValue(...) now accepts optional chartData and, when present, updates the stored chart axis fields in the target field before refresh/dependency recalculation.

3) ChartDataModel now carries axis data as a single coordinates object

Files:

• Sources/JoyfillUI/ViewModels/Models.swift

• Sources/JoyfillUI/ViewModels/DocumentEditor.swift

• Replaced separate axis properties on ChartDataModel (x/y title/min/max) with:

  • chartCoordinates: ChartAxisConfiguration?

• Updated chart model construction in DocumentEditor to populate this coordinates object from field data.

4) Added UI regression coverage

File: JoyfillSwiftUIExample/JoyfillUITests/ChangeUITests/OnChangeHandlerUITests.swift

Added testChartCoordinatess() to validate chart detail synchronization behavior across chart instances/pages by editing one chart configuration and asserting corresponding values are reflected in the paired chart UI.

Design Decisions

• .onChange synchronization in ChartDetailView keeps the existing local edit flow intact while correctly responding to external model updates.
• Single chartCoordinates model property reduces drift risk vs passing six separate axis fields.
• Optional chartData in updateValue keeps non-chart update paths unchanged while enabling full chart updates when axis values are provided.

Public API Impact

No external/public API changes. This PR updates internal view-model wiring and chart state synchronization behavior.

Test Coverage

Added UI test coverage:

• testChartCoordinatess() in OnChangeHandlerUITests

Reviewer Notes

• Scope is now broader than the original description: 5 files changed across view sync, editor change parsing, model shape, and UI regression tests.
• Main functional outcome: chart value elements and axis configuration now stay in sync when updates originate externally, not only from direct local editing.