0fb4c80205
Task #24: Remember the admin's last-used dashboard time range. The admin dashboard's range selector (7d/30d/90d/custom) was resetting to "Last 7 days" on every visit. Now the selected preset range is persisted in localStorage under a per-user key (`admin.statsRange.<userId>`) so each admin sees their last choice on return. Implementation notes: - Edited only artifacts/teaboy-os/src/pages/admin.tsx. - Added two effects: one hydrates the stored value once `user.id` is available (auth loads asynchronously), the other writes to localStorage whenever the range changes after hydration. - Only the preset values (7d/30d/90d) are persisted; "custom" is intentionally not stored since the custom dates are session-scoped and would feel stale on return. After hydration, switching to "custom" leaves the previously stored preset untouched so the next visit still restores the last preset. - Used a hydration guard to avoid clobbering stored values with the default "7d" before the load effect runs.