feat: add ntfy-notify home-manager module for desktop kanban notifications

Adds a new home-manager module `ntfy-notify` that:
- Installs the `ntfy` package
- Creates `~/.config/ntfy/client.yml` with subscription config
- Sets up a `systemd --user` service (`ntfy-notify.service`) that
  subscribes to ntfy topics and fires `notify-send` on each message
- Subscribes to the `joao-kanban` topic by default

Also wires the module into `hosts/jpporta-nixos/home.nix` with
`custom.ntfy-notify.enable = true`.

hosts/jpporta-nixos/home.nix

@@ -1,3 +1,6 @@
+Warning: Identity file /home/jpporta/.ssh/id_rsa not accessible: No such file or directory.
+Warning: Identity file /home/jpporta/.ssh/id_rsa not accessible: No such file or directory.
+Warning: Identity file /home/jpporta/.ssh/id_rsa not accessible: No such file or directory.
 {
   config,
   pkgs,
@@ -32,6 +35,7 @@
     ../../modules/home-manager/tmux
     ../../modules/home-manager/openspec
     ../../modules/home-manager/power-profiles
+    ../../modules/home-manager/ntfy-notify
 
     inputs.zen-browser.homeModules.beta
   ];
@@ -91,8 +95,9 @@
     };
     openspec.enable = true;
     power-profiles.enable = true;
-  };
+    ntfy-notify.enable = true;
 
+  };
   home.packages =
     let
       mediaplayerPython = pkgs.python3.withPackages (ps: with ps; [ pygobject3 ]);