Fix horizontal bar chart tooltip clipping off the right edge

[robsfletch]

Summary

• BarChart's horizontal-orientation tooltip (handleMouseMove and handleKeyDown) pinned the tooltip past the plot's right edge with transform: none and never measured its width — unlike the vertical branch, which already flips the tooltip left when it would overflow.
• Long tooltip content (long series/value labels) got clipped by the consuming app's container.
• Fix mirrors the existing vertical-branch pattern: measure tooltip.offsetWidth, and flip the tooltip to grow leftward from the plot's right edge when it would overflow the container width.

Test plan

• Added BarHorizontalNarrow story (narrow container + long series label) and a new Playwright CT test asserting the tooltip's right edge stays within the container bounds on hover.
• Verified the new test fails against the pre-fix code and passes against the fix.
• npx vitest run: 410/411 pass (1 pre-existing unrelated failure: Icon registry > exports exactly 215 icons, icon count drift unrelated to this change).
• npx playwright test -c playwright-ct.config.ts src/components/Chart/Chart.test.tsx: 69/69 pass.
• npx tsc --noEmit: clean.

Context

Reported downstream in lightsparkdev/analytics#2511 (Agent Analytics dashboard, horizontal bar plot). Consuming repo will bump @lightsparkdev/origin once this is released.

[greptile-apps]

Greptile Summary

This PR keeps horizontal bar-chart tooltips from overflowing the right edge. The main changes are:

• Measures tooltip width during pointer and keyboard interaction.
• Flips overflowing tooltips to the left of the plot edge.
• Adds a narrow-chart fixture and right-edge containment test.

Confidence Score: 4/5

Oversized horizontal tooltips can still be clipped on the left in narrow containers.

• The new right-edge fit check handles the reported overflow.
• The left fallback has no guard for a tooltip wider than the available chart space.
• Pointer and keyboard paths share the same boundary bug.

src/components/Chart/BarChart.tsx

Important Files Changed

Filename	Overview
src/components/Chart/BarChart.tsx	Adds width-aware horizontal tooltip placement, but the fallback can overflow the container's left edge.
src/components/Chart/Chart.test-stories.tsx	Adds a narrow horizontal bar-chart fixture with a long tooltip label.
src/components/Chart/Chart.test.tsx	Adds right-edge containment coverage, but does not check left-edge containment.

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
src/components/Chart/BarChart.tsx:270-272
**Left Flip Can Still Clip**

When the tooltip is wider than `padLeft + plotWidth - TOOLTIP_GAP`, translating it left by its full width produces a negative left edge. In a narrow chart with a long unbroken label, an overflow-clipping container will crop the tooltip on the left instead of the right, so this fallback must constrain both edges.

_{Reviews (1): Last reviewed commit: "Fix horizontal bar chart tooltip clippin..." | Re-trigger Greptile}

[greptile-apps]

Left Flip Can Still Clip

When the tooltip is wider than padLeft + plotWidth - TOOLTIP_GAP, translating it left by its full width produces a negative left edge. In a narrow chart with a long unbroken label, an overflow-clipping container will crop the tooltip on the left instead of the right, so this fallback must constrain both edges.

Context Used: Chart component color and usage conventions (source)

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/components/Chart/BarChart.tsx
Line: 270-272

Comment:
**Left Flip Can Still Clip**

When the tooltip is wider than `padLeft + plotWidth - TOOLTIP_GAP`, translating it left by its full width produces a negative left edge. In a narrow chart with a long unbroken label, an overflow-clipping container will crop the tooltip on the left instead of the right, so this fallback must constrain both edges.

**Context Used:** Chart component color and usage conventions ([source](https://app.greptile.com/lightspark/github/lightsparkdev/origin/-/custom-context?memory=2070e049-47f8-4317-b8d3-707fd915a94b))

How can I resolve this? If you propose a fix, please make it concise.