fix: drop unused totalPages from usePaginatedQuery

totalPages was recomputed from total/limit, duplicating a value both
billing APIs already return deterministically, and the only caller
(UsageLogsTable) never consumed it. Removed it from the composable's
public return instead of keeping unused, potentially drifting state.

Author: claude

src/composables/usePaginatedQuery.test.ts

@@ -54,7 +54,6 @@ describe('usePaginatedQuery', () => {
     expect(fetchPage).toHaveBeenCalledWith({ key: 'a', page: 1, limit: 10 })
     expect(api.items.value).toHaveLength(10)
     expect(api.total.value).toBe(25)
-    expect(api.totalPages.value).toBe(3)
     expect(api.first.value).toBe(0)
     expect(api.loading.value).toBe(false)
   })

src/composables/usePaginatedQuery.ts

@@ -50,9 +50,6 @@ export function usePaginatedQuery<T, K>(
   const page = computed(() => lastResponse.value?.page ?? 1)
   const limit = computed(() => lastResponse.value?.limit ?? initialLimit)
   const total = computed(() => lastResponse.value?.total ?? 0)
-  const totalPages = computed(() =>
-    total.value === 0 ? 0 : Math.ceil(total.value / limit.value)
-  )
   const first = computed(() => (page.value - 1) * limit.value)
 
   let requestToken = 0
@@ -92,7 +89,6 @@ export function usePaginatedQuery<T, K>(
     page,
     limit,
     total,
-    totalPages,
     first,
     loading,
     error,