Fix SidebarLink hover state broken in dark mode

[talissoncosta]

Problem

Hovering a sidebar navigation item in dark mode only changes the icon colour to purple. The text stays white and there is no background highlight. In light mode, hovering changes both icon and text to purple.

Root cause: SidebarLink.tsx uses CSS classes hover-fill-primary and hover-bg-primary that do not exist anywhere in the SCSS. The class that does exist is hover-color-primary (web/styles/project/_utils.scss:9), which handles text colour + child colour + SVG path fill on hover.

Light mode appears to work by coincidence — the text colour change comes from anchor/NavLink default styles, not from the missing utility classes.

Bugs (3 in one file)

Line	Code	Issue
35	hover-fill-primary hover-bg-primary	Non-existent CSS classes — should be hover-color-primary
31	inactiveClassName={activeClassName}	Copy-paste bug — inactive NavLinks receive active class styles
42	fill={'#767D85'}	Hardcoded icon fill overrides any CSS-based fill class

Files

• web/components/navigation/SidebarLink.tsx

Proposed Fix

1. Line 35: Replace hover-fill-primary hover-bg-primary with hover-color-primary
2. Line 31: Change inactiveClassName={activeClassName} to inactiveClassName={inactiveClassName}
3. Line 42: Remove fill={'#767D85'} so the icon inherits colour from the CSS class

Acceptance Criteria

• Sidebar hover works correctly in both light and dark mode
• Inactive NavLinks no longer receive active class styles
• Icon colour adapts to theme via CSS inheritance, not hardcoded hex
• npm run typecheck passes
• npx eslint --fix passes

Context

Part of the design system audit (#6606). See frontend/DESIGN_SYSTEM_ISSUES.md on chore/design-system-audit-6606 branch for full issue list (QW-9).