feat(time-blocks): Add comprehensive time blocking system with contracts

- Add TimeBlock and Holiday models with recurrence support (one-time, weekly, monthly, yearly, holiday)
- Implement business-level and resource-level blocking with hard/soft block types
- Add multi-select holiday picker for bulk holiday blocking
- Add calendar overlay visualization with distinct colors:
  - Business blocks: Red (hard) / Yellow (soft)
  - Resource blocks: Purple (hard) / Cyan (soft)
- Add month view resource indicators showing 1/n width per resource
- Add yearly calendar view for block overview
- Add My Availability page for staff self-service
- Add contracts module with templates, signing flow, and PDF generation
- Update scheduler with click-to-day navigation in week view

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/components/Sidebar.tsx

@@ -15,6 +15,8 @@ import {
   HelpCircle,
   Clock,
   Plug,
+  FileSignature,
+  CalendarOff,
 } from 'lucide-react';
 import { Business, User } from '../types';
 import { useLogout } from '../hooks/useAuth';
@@ -121,6 +123,14 @@ const Sidebar: React.FC<SidebarProps> = ({ business, user, isCollapsed, toggleCo
             isCollapsed={isCollapsed}
             locked={!canUse('plugins') || !canUse('tasks')}
           />
+          {(role === 'staff' || role === 'resource') && (
+            <SidebarItem
+              to="/my-availability"
+              icon={CalendarOff}
+              label={t('nav.myAvailability', 'My Availability')}
+              isCollapsed={isCollapsed}
+            />
+          )}
         </SidebarSection>
 
         {/* Manage Section - Staff+ */}
@@ -145,12 +155,26 @@ const Sidebar: React.FC<SidebarProps> = ({ business, user, isCollapsed, toggleCo
               isCollapsed={isCollapsed}
             />
             {canViewAdminPages && (
-              <SidebarItem
-                to="/staff"
-                icon={Users}
-                label={t('nav.staff')}
-                isCollapsed={isCollapsed}
-              />
+              <>
+                <SidebarItem
+                  to="/staff"
+                  icon={Users}
+                  label={t('nav.staff')}
+                  isCollapsed={isCollapsed}
+                />
+                <SidebarItem
+                  to="/contracts"
+                  icon={FileSignature}
+                  label={t('nav.contracts', 'Contracts')}
+                  isCollapsed={isCollapsed}
+                />
+                <SidebarItem
+                  to="/time-blocks"
+                  icon={CalendarOff}
+                  label={t('nav.timeBlocks', 'Time Blocks')}
+                  isCollapsed={isCollapsed}
+                />
+              </>
             )}
           </SidebarSection>
         )}