redesign: rename Project→Client, finance single-card + filters, mobile tasks, sticky headers

- Rename "Project" → "Client" across UI (labels + /projects→/clients routes with redirect); normalize company-meaning labels to "Company"
- Finance tabs: merge dual cards into one per tab, add header column filters (expenses/subs/invoices), overview as 3-section card, move +Expense/+Invoice to card right edge
- Tasks: responsive mobile stats grid, progressive column hiding (min Status+Name+Assigned), sidebar mobile footer (profile/theme/signout)
- Hide Company column for single-company users; +Task shows disabled Company field instead of hiding
- Sticky table headers site-wide with opaque card background
- Pin dev server to port 5173

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/App.jsx

@@ -64,7 +64,12 @@ const ClientMyInvoices = lazy(() => import('./pages/client/ClientMyInvoices'));
 
 function RedirectProjectDetail() {
   const { id } = useParams();
-  return <Navigate to={`/projects/${id}`} replace />;
+  return <Navigate to={`/clients/${id}`} replace />;
+}
+
+function RedirectClientDetail() {
+  const { id } = useParams();
+  return <Navigate to={`/clients/${id}`} replace />;
 }
 
 function RedirectToTask() {
@@ -99,7 +104,8 @@ export default function App() {
           <Route path="/" element={<Login />} />
 
           <Route path="/dashboard" element={<ProtectedRoute role={['team', 'external', 'client']}><TeamDashboard /></ProtectedRoute>} />
-          <Route path="/projects/:id" element={<ProtectedRoute role={['team', 'external', 'client']}><ProjectDetailPage /></ProtectedRoute>} />
+          <Route path="/clients/:id" element={<ProtectedRoute role={['team', 'external', 'client']}><ProjectDetailPage /></ProtectedRoute>} />
+          <Route path="/projects/:id" element={<RedirectClientDetail />} />
           <Route path="/tasks/:id" element={<ProtectedRoute role={['team', 'external', 'client']}><TaskDetail /></ProtectedRoute>} />
           <Route path="/company" element={<ProtectedRoute role={['team', 'client']}><CompaniesPage /></ProtectedRoute>} />
           <Route path="/company/:id" element={<ProtectedRoute role={['team', 'client']}><CompanyDetail /></ProtectedRoute>} />