feat(estimates): add EstimatesPage hub with templates tab, estimate detail drawer, and template editor

- EstimatesPage: tabbed hub with Estimates and Templates tabs, KPI strip, search + filter
- EstimateDetailModal: right-side drawer showing scope of work, computed line items, and financial summary from template + roof area
- TemplateEditorModal: create/edit/duplicate templates with segmented mode toggle
- Owner-only template management (create, edit, duplicate, delete); Admin/FA read-only view
- Duplicate mode: toggle between 'Save as new copy' (default, editable name) and 'Replace original'
- MASTER_TEMPLATES and MOCK_ESTIMATES moved into mockStore with full CRUD helpers
- TemplateSelectionModal now reads from mockStore instead of local stub
- Sidebar nav updated to point to /estimates hub for all roles
- Routes added: /emp/fa/estimates, /admin/estimates, /owner/estimates

src/components/estimates/TemplateSelectionModal.jsx

@@ -1,4 +1,5 @@
 import React, { useState } from 'react';
+import { useMockStore } from '../../data/mockStore';
 
 const STUBBED_TEMPLATES = [
     {
@@ -531,10 +532,11 @@ const STUBBED_TEMPLATES = [
 ];
 
 export default function TemplateSelectionModal({ isOpen, onClose, onSelectTemplate }) {
+    const { templates } = useMockStore();
     const [searchTerm, setSearchTerm] = useState('');
     const [selected, setSelected] = useState(null);
 
-    const filtered = STUBBED_TEMPLATES.filter(t =>
+    const filtered = templates.filter(t =>
         t.name.toLowerCase().includes(searchTerm.toLowerCase()) ||
         t.category.toLowerCase().includes(searchTerm.toLowerCase())
     );
@@ -579,7 +581,7 @@ export default function TemplateSelectionModal({ isOpen, onClose, onSelectTempla
                         {/* Category Header */}
                         <div className="px-4 py-3 bg-blue-50/50 dark:bg-blue-900/10 border-b border-zinc-200 dark:border-white/10">
                             <h3 className="text-sm font-semibold text-blue-600 dark:text-blue-400">
-                                Roofing ({filtered.length})
+                                Templates ({filtered.length})
                             </h3>
                         </div>