feat: timeline multi-select, demand popover, resource hover card, merged tooltips, dark mode fixes

Major timeline enhancements:
- Right-click drag multi-selection with floating action bar (batch delete/assign)
- DemandPopover for demand strip details (replaces broken "Loading" modal)
- ResourceHoverCard on name hover showing skills, rates, role, chapter
- Merged heatmap+vacation tooltips into unified TimelineTooltip component
- Fixed overbooking blink animation (date normalization, z-index ordering)
- Fixed dark mode sticky column bleed-through in project view
- System roles admin page, notification task management, performance review docs

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/next.config.ts

@@ -2,6 +2,9 @@ import path from "path";
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
+  experimental: {
+    optimizePackageImports: ["recharts", "date-fns"],
+  },
   transpilePackages: [
     "@planarchy/api",
     "@planarchy/db",