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/Layout.jsx

@@ -145,7 +145,7 @@ const Layout = () => {
                         icon: LayoutDashboard,
                         label: <span><span className="text-[#fda913]">Pro</span>Canvas</span>
                     },
-                    { to: "/owner/estimate", icon: Calculator, label: "Estimate Builder" },
+                    { to: "/owner/estimates", icon: Calculator, label: "Estimates" },
                     { to: "/admin/schedule", icon: Calendar, label: "Team Schedule" },
                     { to: "/admin/leaderboard", icon: Trophy, label: "Leaderboard" },
                     ...commonItems,
@@ -163,7 +163,7 @@ const Layout = () => {
                         icon: LayoutDashboard,
                         label: <span><span className="text-[#fda913]">Pro</span>Canvas</span>
                     },
-                    { to: "/admin/estimate", icon: Calculator, label: "Estimate Builder" },
+                    { to: "/admin/estimates", icon: Calculator, label: "Estimates" },
                     ...commonItems,
                 ];
             case 'CONTRACTOR':
@@ -189,7 +189,7 @@ const Layout = () => {
                         icon: LayoutDashboard,
                         label: <span><span className="text-[#fda913]">Pro</span>Canvas</span>
                     },
-                    { to: "/emp/fa/estimate", icon: Calculator, label: "Estimate Builder" },
+                    { to: "/emp/fa/estimates", icon: Calculator, label: "Estimates" },
                     ...commonItems,
                 ];
             default: // Customer or Fallback