fix(miners): close list tooltips on scroll so they don't float outside the table

[jerryzai]

Summary

Problem

On the OSS contributions page (miners list view), the username and PR/issue activity-dot tooltips stayed open while the user scrolled the table body. Because the tooltip portal tracks its anchor, the tooltip floated over the sticky toolbar / outside the table once its row scrolled away.

Fix

Swap the in-table Tooltips in MinersList.tsx for ScrollAwareTooltip (existing helper from #876) for the username cell and the activity segment dots. It auto-closes any open tooltip on scroll, so a tooltip can no longer outlive the visible position of its anchor.

Sticky-header tooltips (view-mode toggle, eligibility filter) are unchanged — they don't scroll, so the regular Tooltip is fine.

Test plan

• OSS contributions page → list view
• Hover a truncated miner username → tooltip shows; scroll the table → tooltip closes immediately
• Hover a PR/issue activity dot ("Merged"/"Open"/"Closed") → tooltip shows; scroll → tooltip closes
• View-mode toggle and eligibility filter tooltips in the sticky header still work normally

Related Issues

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Screenshots

Before:

bandicam.2026-05-01.09-39-14-282.mp4

Now:

bandicam.2026-05-01.09-39-58-381.mp4

Checklist

• New components are modularized/separated where sensible
• Uses predefined theme (e.g. no hardcoded colors)
• Responsive/mobile checked
• Tested against the test API
• npm run format and npm run lint:fix have been run
• npm run build passes
• Screenshots included for any UI/visual changes