refactor: replace role/policy modals with separate pages

- Create AdminRoleEdit.tsx for /admin/roles/create and /admin/roles/:id/edit
- Create AdminPolicyEdit.tsx for /admin/policies/create and /admin/policies/:id/edit
- Remove create/edit modals from AdminRoles.tsx and AdminPolicies.tsx
- Add new lazy routes in App.tsx with proper permission gates
- Keep delete confirmation as small inline modal (appropriate for destructive action)

src/App.tsx

@@ -91,8 +91,10 @@ const AdminPinnedMessageCreate = lazy(() => import('./pages/AdminPinnedMessageCr
 const AdminChannelSubscriptions = lazy(() => import('./pages/AdminChannelSubscriptions'));
 const AdminEmailTemplatePreview = lazy(() => import('./pages/AdminEmailTemplatePreview'));
 const AdminRoles = lazy(() => import('./pages/AdminRoles'));
+const AdminRoleEdit = lazy(() => import('./pages/AdminRoleEdit'));
 const AdminRoleAssign = lazy(() => import('./pages/AdminRoleAssign'));
 const AdminPolicies = lazy(() => import('./pages/AdminPolicies'));
+const AdminPolicyEdit = lazy(() => import('./pages/AdminPolicyEdit'));
 const AdminAuditLog = lazy(() => import('./pages/AdminAuditLog'));
 
 function ProtectedRoute({ children }: { children: React.ReactNode }) {
@@ -892,6 +894,26 @@ function App() {
             </PermissionRoute>
           }
         />
+        <Route
+          path="/admin/roles/create"
+          element={
+            <PermissionRoute permission="roles:create">
+              <LazyPage>
+                <AdminRoleEdit />
+              </LazyPage>
+            </PermissionRoute>
+          }
+        />
+        <Route
+          path="/admin/roles/:id/edit"
+          element={
+            <PermissionRoute permission="roles:edit">
+              <LazyPage>
+                <AdminRoleEdit />
+              </LazyPage>
+            </PermissionRoute>
+          }
+        />
         <Route
           path="/admin/roles/assign"
           element={
@@ -912,6 +934,26 @@ function App() {
             </PermissionRoute>
           }
         />
+        <Route
+          path="/admin/policies/create"
+          element={
+            <PermissionRoute permission="roles:create">
+              <LazyPage>
+                <AdminPolicyEdit />
+              </LazyPage>
+            </PermissionRoute>
+          }
+        />
+        <Route
+          path="/admin/policies/:id/edit"
+          element={
+            <PermissionRoute permission="roles:edit">
+              <LazyPage>
+                <AdminPolicyEdit />
+              </LazyPage>
+            </PermissionRoute>
+          }
+        />
         <Route
           path="/admin/audit-log"
           element={