fix(ui): remove blue-shifted hardcoded colors from timeline components

Replace hardcoded blue-shifted rgba values and slate-* classes with neutral
CSS variable references in timeline resource/project panels, tooltips,
constants, and heatmap mono palette. Change utilization row tint from blue
to green. Replace slate-950 open demand backgrounds with --surface-card.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/components/timeline/TimelineTooltip.tsx

@@ -285,7 +285,7 @@ export function TimelineTooltip({
         tooltipRef={demandTooltipRef}
         dataTestId="timeline-demand-tooltip"
         position={demandTooltipPos}
-        backgroundColor="rgba(3, 7, 18, 0.96)"
+        backgroundColor="rgba(10, 10, 10, 0.96)"
         className="fixed z-40 max-w-sm pointer-events-none rounded-xl border border-gray-800 bg-gray-950/96 px-3 py-2 text-xs text-white shadow-2xl"
       >
         <div className="flex items-start justify-between gap-3">
@@ -359,7 +359,7 @@ export function TimelineTooltip({
           (vacationTooltipRef as React.MutableRefObject<HTMLDivElement | null>).current = null;
         }}
         position={heatmapTooltipPos}
-        backgroundColor="rgba(3, 7, 18, 0.96)"
+        backgroundColor="rgba(10, 10, 10, 0.96)"
         className="fixed z-40 max-w-sm pointer-events-none rounded-xl border border-gray-800 bg-gray-950/96 px-3 py-2 text-xs text-white shadow-2xl"
       >
         <div className="flex items-center justify-between gap-3">
@@ -388,7 +388,7 @@ export function TimelineTooltip({
       <TooltipSurface
         tooltipRef={heatmapTooltipRef}
         position={heatmapTooltipPos}
-        backgroundColor="rgba(3, 7, 18, 0.96)"
+        backgroundColor="rgba(10, 10, 10, 0.96)"
         className="fixed z-40 max-w-sm pointer-events-none rounded-xl border border-gray-800 bg-gray-950/96 px-3 py-2 text-xs text-white shadow-2xl"
       >
         <div className="flex items-center justify-between gap-3">