• Removed obsolete `sidebarIconColors` map and `getItemColor` util from
SiderBar/render; all selected states now use the single CSS variable
`--semi-color-primary` for both text and icons.
• Simplified `getLucideIcon`:
– Added `Package` to Lucide imports.
– Switched “models” case to `<Package />`, avoiding duplication with
the Layers glyph.
– Replaced per-key color logic with `iconColor` derived from the new
uniform highlight color.
• Stripped any unused imports / dead code paths after the refactor.
• Lint passes; sidebar hover/focus behavior unchanged while visual
consistency is improved.
