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/src/server/auth.ts

@@ -28,6 +28,12 @@ const authConfig = {
         const isValid = await verify(user.passwordHash, password);
         if (!isValid) return null;
 
+        // Track last login time
+        await prisma.user.update({
+          where: { id: user.id },
+          data: { lastLoginAt: new Date() },
+        });
+
         return {
           id: user.id,
           email: user.email,