add flatpak apps for workstation

infrastructure/graduated/arch/workstation.md

@@ -961,4 +961,22 @@ Create a new project in the current directory
 
 ```bash
 poetry new .
-```
+```
+
+## Note Taking
+
+```bash
+flatpak install org.kde.marknote
+```
+
+## Calculator
+
+```bash
+flatpak install org.gnome.Calculator
+```
+
+## Disk Usqage
+
+```bash
+flatpak install org.gnome.baobab
+```