feat(frontend): update allocation UI and services

Enhance allocation management interface:
- Allocations page: modal-based editing, variance display
- Updated services: allocationService with bulk ops, projectMonthPlanService
- Project and team member pages: reconciliation status indicators
- Navigation config: add planning and reports links

Part of enhanced-allocation change.

frontend/src/lib/config/navigation.ts

@@ -5,6 +5,7 @@ export const navigationSections: NavSection[] = [
     title: 'PLANNING',
     items: [
       { label: 'Dashboard', href: '/dashboard', icon: 'LayoutDashboard' },
+      { label: 'Planning', href: '/planning', icon: 'CalendarCheck' },
       { label: 'Team Members', href: '/team-members', icon: 'Users' },
       { label: 'Projects', href: '/projects', icon: 'Folder' },
       { label: 'Allocations', href: '/allocations', icon: 'Calendar' },