rename: temp_16tb -> Poup_16T throughout

- Module renamed to poup-16t-disk.nix
- Option namespace: gortium.poup16t (was gortium.temp16tb)
- LUKS name: poup_16t (was temp_16tb)
- Mount point: /mnt/Poup_16T (was /mnt/temp_16tb)
- btrbk instance: poup16t (was temp16tb)
- flake.nix import and host config updated

flake.nix

@@ -65,7 +65,7 @@
               ./hosts/lazyworkhorse/configuration.nix
               ./hosts/lazyworkhorse/hardware-configuration.nix
               ./modules/nixos/filesystem/hoardingcow-mount.nix
-              ./modules/nixos/filesystem/temp-16tb-disk.nix
+              ./modules/nixos/filesystem/poup-16t-disk.nix
               ./modules/nixos/services/docker_manager.nix
               ./modules/nixos/services/open_code_server.nix
               ./modules/nixos/services/ollama_init_custom_models.nix