fix: code review fixes

- Fix hardcoded user path in webapps.nix (use homeDirectory)
- Normalize wallpapers option to use .enable suffix
- Remove duplicate FZF keybind declaration
- Update comments to match actual implementation

hosts/m3-hermes/default.nix

@@ -10,7 +10,7 @@
   extraServices = {
     flatpak.enable = false;
     ollama.enable = false;
-    podman.enable = true;
+    podman.enable = false;
     virtualisation.enable = false;
   };
 }