Upgrade Downloads Graph Dependencies

[Sewer56]

fixes LAZ-199

Summary

DownloadGraph blocks the React 17 migration because it depends on
react-resize-detector@4.2.3 and recharts@1.8.6, both of which only support
React 16 as a peer dependency.

This PR updates/replaces those dependencies without changing Downloads page
behaviour (expand/collapse, resize handling, recent speed history, bandwidth-limit line).

See LAZ-199 for details.

Changes

Dependency updates

• Remove react-resize-detector from catalog, src/main/package.json, and src/renderer/package.json
• Upgrade recharts from ^1.8.5 → ^2.15.4 (React 17 support since 2.0.3)

DownloadGraph.tsx

• Replace react-resize-detector with native ResizeObserver
• Update setRef to store container ref and observe resize via ResizeObserver
• Remove truthy import (no longer needed)

charts.scss

• Update .recharts-area selectors: use .recharts-area-area / .recharts-area-curve class names instead of :first-child / :last-child pseudo-selectors (recharts 2.x changed markup structure)

Test coverage

• Add DownloadGraph.test.tsx covering:
  • ResizeObserver triggers chart width update
  • disconnect() called on unmount
  • Bandwidth limit label rendered when maxBandwidth constrains the graph

Config

• Add vitest.config.mts glob to vitest.config.ts projects

Acceptance criteria

• No active dependency path for the Downloads graph uses react-resize-detector@4.2.3 or recharts@1.8.6
• Graph still renders above the downloads table, expands/collapses, resizes with container, updates from speedHistory, shows bandwidth-limit line
• Current no-animation behaviour preserved
• Build, test, lint, format pass
• Manual smoke-test of Downloads page graph