feat(sprint-5): Phase 5 — Wire reports + portal to React Query

- Reports: preview queries + apiDownload for PDF/CSV
- Portal dashboard: usePortalDashboardQuery with quota fallback
- Portal history: usePortalHistoryQuery with month filter
- Portal profile: usePortalProfileQuery + useChangePasswordMutation
- All pages show loading skeletons, graceful mock fallback

cannamanage-frontend/src/services/portal.ts

@@ -1,4 +1,4 @@
-import { useQuery } from "@tanstack/react-query"
+import { useMutation, useQuery } from "@tanstack/react-query"
 
 import { apiClient } from "@/lib/api-client"
 
@@ -81,3 +81,20 @@ export function usePortalProfileQuery() {
     staleTime: 5 * 60 * 1000, // profile rarely changes
   })
 }
+
+// --- Mutations ---
+
+export interface ChangePasswordPayload {
+  currentPassword: string
+  newPassword: string
+}
+
+export function useChangePasswordMutation() {
+  return useMutation({
+    mutationFn: (payload: ChangePasswordPayload) =>
+      apiClient<void>("/portal/password", {
+        method: "PUT",
+        body: payload,
+      }),
+  })
+}