ERA-8882 Show polygon area when measuring with the map ruler

[jeslefcourt]

What

Shows the area of the polygon outlined by the map ruler's segments once three or more vertices exist.

• While drawing: the cursor popup gains an Area: line between the existing Bearing: and Distance: lines. The polygon is the committed points plus the current cursor position, closed back to the first point, so the value updates live with mouse movement, clicks, and point drags — per the ticket's acceptance criteria it appears from 2 committed points onward.
• After finishing: each selected point's popup shows the measured polygon's area alongside bearing and distance-from-start.

Area is computed with turf (polygon + area) and displayed in km² to 2 decimals, consistent with the existing km distance readout. Shared helpers live in src/MapRulerControl/utils.js.

How

DefaultCursorPopup in MapDrawingTools takes an optional area prop (default null) injected via the existing renderCursorPopup override, so other consumers (e.g. ReportGeometryDrawer) are unaffected. New i18n keys pointPopup.areaLabel and mapDrawingTools.areaLabel in all six locales; I18N_FILES_VERSION bumped to 1.44.

Testing

New unit coverage for the area helpers (ring gating, cursor-vertex handling), the point popup (area absent below 3 points, present at 3+, shown on non-last points), and the cursor popup (paragraph order bearing → area → distance; unchanged without area). yarn test src/MapRulerControl src/MapDrawingTools: 3 suites, 26 tests passing; consumer suites (ReportGeometryDrawer, AreaPicker) unaffected. ESLint/stylelint at pre-existing baseline.

ERA-8882

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds live polygon area measurement to the map ruler tool (MapRulerControl), showing area while drawing (cursor popup) and after finishing (point popups), with shared area-formatting helpers and i18n support.

Changes:

• Introduces area calculation/formatting helpers for ruler points (including cursor-as-vertex handling) and unit tests for those helpers.
• Updates the map ruler cursor popup and point popups to display polygon area when 3+ vertices exist.
• Adds new translation keys across all supported locales and bumps the i18n file version.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/MapRulerControl/utils.js	Adds turf-based area helpers for closed-ring polygon area display (incl. cursor vertex).
src/MapRulerControl/utils.test.js	Unit tests covering ring gating, closure, and cursor handling.
src/MapRulerControl/PointPopup.js	Displays polygon area on point popups when 3+ points exist.
src/MapRulerControl/PointPopup.test.js	Verifies area presence/absence behavior in point popups.
src/MapRulerControl/index.js	Injects computed area into the cursor popup via renderCursorPopup.
src/MapDrawingTools/index.js	Extends DefaultCursorPopup to optionally render an area line.
src/MapDrawingTools/index.test.js	Adds tests for DefaultCursorPopup area rendering and ordering.
src/i18n.js	Bumps I18N_FILES_VERSION to pick up updated locale JSON.
public/locales/*/map-controls.json	Adds mapDrawingTools.areaLabel and pointPopup.areaLabel translations.

[jeslefcourt]

Added in 82fd3d1: while the ruler is active, the measured polygon is now lightly shaded (same red as the polygon-draw fill at 0.1 opacity), tracking the cursor live while drawing via a new opt-in showLineFill prop on MapDrawingTools — default off, so other consumers are untouched.

This also wraps the ruler's MapDrawingTools in its own MapDrawingToolsContextProvider. Without it, the ruler's fill polygon would flow into the shared drawing context that AreaPicker reads when isPickingLocation flips false, silently replacing an open event's area with the ruler shape (a latent version of a pre-existing empty-geometry leak). A regression test covers the isolation.

[Copilot]

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