refactor(db): thread context.Context through all Store methods

Enables request-scoped cancellation, timeouts, and graceful shutdown
for all database operations across API handlers, CLI commands, and TUI.

cmd/cards.go

@@ -26,7 +26,7 @@ func init() {
 	rootCmd.AddCommand(cardsCmd)
 }
 
-func runCards(_ *cobra.Command, _ []string) error {
+func runCards(cmd *cobra.Command, _ []string) error {
 	store, err := openStore()
 	if err != nil {
 		return err
@@ -49,7 +49,7 @@ func runCards(_ *cobra.Command, _ []string) error {
 		p.CardTypeFilter = &ct
 	}
 
-	entities, err := store.List(p)
+	entities, err := store.List(cmd.Context(), p)
 	if err != nil {
 		return err
 	}