feat(leads): Phase 8 — Save action, lead list page, and nav update

Save action (CreateLeadPage):
- Validate required fields: first/last name, 10-digit phone, address, city, lead source
- On failure: Sonner error toast + auto-opens first incomplete section
- On success: Sonner success toast with name + address, redirects to /emp/fa/leads
- Desktop save bar with progress % indicator and validation error message
- Back button navigates to /emp/fa/leads instead of browser history

Leads List page (LeadsListPage.jsx):
- Route: /emp/fa/leads (FIELD_AGENT, ADMIN, OWNER)
- Lead cards: name, urgency + status badges, address, phone, lead source, time ago, creator
- Search bar: filters by name, address, city, source, status
- Empty state with CTA when no leads saved yet
- Animated card entrance with staggered spring transitions

mockStore:
- Add leads[] state and addLead() action — prepends new lead with id, createdAt, status: New

Navigation:
- Sidebar "New Lead" replaced with "Leads" (ClipboardList icon) for all roles
- New Lead button lives on the list page header

Author: Satyam Rastogi

src/App.jsx

@@ -30,6 +30,7 @@ import VendorOrders from './pages/vendor/VendorOrders';
 import ContractorDashboard from './pages/contractor/ContractorDashboard';
 import SubContractorDashboard from './pages/subcontractor/SubContractorDashboard';
 import CreateLeadPage from './pages/CreateLeadPage';
+import LeadsListPage from './pages/LeadsListPage';
 
 // ... (existing imports)
 const ProtectedRoute = ({ children, allowedRoles }) => {
@@ -107,6 +108,14 @@ function App() {
                 </ProtectedRoute>
               }
             />
+            <Route
+              path="/emp/fa/leads"
+              element={
+                <ProtectedRoute allowedRoles={['FIELD_AGENT', 'ADMIN', 'OWNER']}>
+                  <LeadsListPage />
+                </ProtectedRoute>
+              }
+            />
             <Route
               path="/emp/fa/leads/new"
               element={