fix(charts): restore Safari SVG paints and clip reveals (#410)

[grootbro]

Summary

• Sanitize React useId() values used in SVG url(#…) / mask / clipPath so Safari can resolve paint servers
• Prefer SVG presentation attributes for gradient stopColor/stopOpacity, and replace relative oklch(from …) chart strokes/tokens with var(--border) / color-mix
• Skip Motion-driven clipPath width animation on Safari (CSS width on clip rect stays at 0 there)

Fixes #410

Test plan

• Open Events Stats + funnel charts in Safari 26.x (macOS Tahoe) — series, fills, and grids render (not blank/clipped)
• Same charts in Chrome/Firefox — reveal animation and paints unchanged
• Hover highlight / dash-tail overlays still work
• CI: sanitizeSvgId unit tests pass

Summary by CodeRabbit

• Bug Fixes

  • Improved chart rendering compatibility in Safari, including gradients, masks, clip paths, and animated reveals.
  • Improved SVG identifier handling for reliable chart rendering across browsers.
  • Updated chart colors, reference lines, and transparency for more consistent theme rendering.

• Tests

  • Added coverage for valid and sanitized SVG identifiers.

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📥 Commits

Reviewing files that changed from the base of the PR and between e3c15fa and ba3a40a.

📒 Files selected for processing (1)

• apps/start/src/components/charts/line.tsx

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📝 Walkthrough

Walkthrough

Chart components now use sanitized SVG identifiers and direct SVG gradient attributes. Safari uses static chart reveal clips. Chart reference lines and transparency tokens use shared CSS color values.

Changes

Chart SVG compatibility

Layer / File(s)	Summary
SVG identifier foundation apps/start/src/components/charts/sanitize-svg-id.ts, apps/start/src/components/charts/sanitize-svg-id.test.ts, apps/start/src/components/charts/use-svg-id.ts	Adds SVG ID sanitization, the useSvgId hook, and tests for React ID formats.
Chart SVG references and stops apps/start/src/components/charts/area.tsx, apps/start/src/components/charts/bar.tsx, apps/start/src/components/charts/dash-tail-stroke.tsx, apps/start/src/components/charts/grid.tsx, apps/start/src/components/charts/highlight-segment.tsx, apps/start/src/components/charts/line.tsx, apps/start/src/components/charts/area-gradient-defs.tsx, apps/start/src/components/charts/tooltip/tooltip-indicator.tsx	Chart paint and clip-path identifiers use useSvgId. Gradient stops use stopColor and stopOpacity attributes.
Safari reveal rendering apps/start/src/components/charts/chart-reveal-clip.tsx	Safari detection selects a static padded clip rectangle. Other environments keep the animated reveal rectangle.

Chart color tokens

Layer / File(s)	Summary
Chart color definitions apps/start/src/components/overview/overview-metrics.tsx, apps/start/src/components/report-chart/*/chart.tsx, apps/start/src/styles.css	Reference lines use var(--border). Previous-line color uses var(--chart-crosshair). Transparency tokens use color-mix.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to ba3a4

Chart gradients now use Safari-compatible identifiers and SVG attributes, with no concrete current-head merge-blocking risk identified.

Sequence Diagram(s)

sequenceDiagram
  participant Browser
  participant ChartRevealClip
  participant SVGClipPath
  Browser->>ChartRevealClip: provide user agent
  ChartRevealClip->>ChartRevealClip: detect Safari after mount
  ChartRevealClip->>SVGClipPath: render static padded clip rectangle on Safari
  ChartRevealClip->>SVGClipPath: render animated reveal rectangle otherwise

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🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 15 functions across 17 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the primary change: restoring Safari SVG paint and clip reveal behavior.
Linked Issues check	✅ Passed	The changes directly address issue [#410] by sanitizing SVG IDs, preserving gradient rendering, replacing incompatible CSS color syntax, and disabling Safari-incompatible clip reveal animation. Unit t…
Out of Scope Changes check	✅ Passed	The CSS token, reference-line, gradient, SVG ID, and Safari animation changes support the stated objective for [#410]. No unrelated code changes are evident.

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Actionable comments posted: 1

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Inline comments:
In `@apps/start/src/components/charts/line.tsx`:
- Line 95: Update the gradient identifier construction near useSvgId in the Line
component to call useSvgId("line-gradient") directly, replacing the two-step ID
composition so the complete SVG gradient ID is sanitized. Preserve the existing
gradient reference behavior while avoiding unsanitized dataKey content.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: 27310a2e-9fd5-4371-9221-63802bff80fd

📥 Commits

Reviewing files that changed from the base of the PR and between 3060ca1 and e3c15fa.

📒 Files selected for processing (18)

• apps/start/src/components/charts/area-gradient-defs.tsx
• apps/start/src/components/charts/area.tsx
• apps/start/src/components/charts/bar.tsx
• apps/start/src/components/charts/chart-reveal-clip.tsx
• apps/start/src/components/charts/dash-tail-stroke.tsx
• apps/start/src/components/charts/grid.tsx
• apps/start/src/components/charts/highlight-segment.tsx
• apps/start/src/components/charts/line.tsx
• apps/start/src/components/charts/sanitize-svg-id.test.ts
• apps/start/src/components/charts/sanitize-svg-id.ts
• apps/start/src/components/charts/tooltip/tooltip-indicator.tsx
• apps/start/src/components/charts/use-svg-id.ts
• apps/start/src/components/overview/overview-metrics.tsx
• apps/start/src/components/report-chart/area/chart.tsx
• apps/start/src/components/report-chart/conversion/chart.tsx
• apps/start/src/components/report-chart/histogram/chart.tsx
• apps/start/src/components/report-chart/line/chart.tsx
• apps/start/src/styles.css

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[grootbro]

Addressed CodeRabbit: full gradient id goes through useSvgId(line-gradient-${dataKey}) so Safari-safe even when dataKey contains :.