fix: remove dead shareStockStatus gating from shared medication overview (#436)

The shareStockStatus UI toggle was replaced by shareMedicationOverview in
commit e0fb77d, but the backend gating logic was left intact. Users who
had previously set shareStockStatus=false were stuck with empty stock
values ('-') on the shared medication overview with no UI to change it.

- Remove showStockStatus parameter from buildSharedMedicationOverview()
- Remove visibility gating that nullified stock fields
- Remove shareStockStatus from settings API responses and PUT schema
- Remove shareStockStatus from frontend types, hooks, and context
- Clean up all related test fixtures and dead test cases
- DB column share_stock_status retained (never remove columns)

frontend/src/types/index.ts

@@ -253,7 +253,6 @@ export type SharedScheduleData = {
 		expiryWarningDays?: number;
 	};
 	stockCalculationMode?: "automatic" | "manual";
-	shareStockStatus?: boolean;
 	shareMedicationOverview?: boolean;
 	medicationOverview?: SharedMedicationOverviewItem[] | null;
 	upcomingTodayOnly?: boolean;