Convert the remaining dynamic and hardcoded inline styles to Tailwind utilities

Second styling pass over the components and pages: move conditional theme colors into className ternaries (bg-accent / bg-surface-hover etc.), turn reused CSSProperties constants into className constants, and express static hardcoded hex/rgba colors as Tailwind arbitrary values so the exact rendered colour is preserved. Truly dynamic styling (computed geometry, gradients, multi-part shadows, data-driven colours, the undefined --sidebar/--nav layout vars) stays inline as it cannot be expressed as a static class. Updated three component tests that asserted the old inline active-state styles to assert the equivalent utility class instead.

Verified: client typecheck 0, full client suite green, and a live light/dark render check in the dev server confirms the semantic theme tokens resolve correctly (the earlier 'transparent popups' were a stale dev server that pre-dated the tailwind.config token addition, not a code issue).

client/src/components/Map/MapView.tsx

@@ -515,8 +515,7 @@ export const MapView = memo(function MapView({
       center={center}
       zoom={zoom}
       zoomControl={false}
-      className="w-full h-full"
-      style={{ background: '#e5e7eb' }}
+      className="w-full h-full bg-[#e5e7eb]"
     >
       <TileLayer
         url={tileUrl}