feat: add ntfy-notify home-manager module for desktop kanban notifications (#1)

Adds a new home-manager module `ntfy-notify` that delivers kanban state changes as Linux desktop notifications via **ntfy.sh** + `notify-send` → SwayNC.

**What it does:**
- Installs `ntfy` package
- Creates `~/.config/ntfy/client.yml` with subscription to the `joao-kanban` topic
- Sets up `ntfy-notify.service` (systemd --user) as a persistent subscriber
- Each incoming message fires `notify-send -u critical` → picked up by SwayNC
- Configurable: `server` URL, `subscriptions` list, per-topic priority

**Usage:**
After deploy, start the service once:
```bash
systemctl --user daemon-reload
systemctl --user start ntfy-notify
```

**Companion:** A cron job on the VPS will be needed to push kanban events to the ntfy topic (separate task).

Closes kanban task t_322419fa on ndots board.

---------

Co-authored-by: hermes-bot <hermes@srv1239749>
Reviewed-on: #1

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 ]);

modules/home-manager/ntfy-notify/default.nix

@@ -0,0 +1,90 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.custom.ntfy-notify;
+
+  # Escape the whole command string for the YAML config. Since ntfy reads this
+  # from client.yml directly (not from systemd), we pass notify-send arguments
+  # as a shell command string — ntfy will spawn a shell to run it.
+  mkSubscription = topic: priority:
+    lib.generators.toYaml { } [{
+      topic = "${cfg.server}/${topic}";
+      command = ''notify-send -a "Kanban" -u "${priority}" "Kanban Update" "''${m}"'';
+    }];
+in
+{
+  options.custom.ntfy-notify = {
+    enable = lib.mkEnableOption "ntfy desktop notification subscriber";
+
+    server = lib.mkOption {
+      type = lib.types.str;
+      default = "ntfy.sh";
+      description = "ntfy server base URL (e.g. ntfy.sh or self-hosted).";
+    };
+
+    subscriptions = lib.mkOption {
+      type = lib.types.listOf (lib.types.submodule {
+        options = {
+          topic = lib.mkOption {
+            type = lib.types.str;
+            description = "ntfy topic to subscribe to.";
+          };
+          priority = lib.mkOption {
+            type = lib.types.enum [ "low" "normal" "critical" ];
+            default = "normal";
+            description = "Urgency level passed to notify-send -u.";
+          };
+        };
+      });
+      default = [
+        {
+          topic = "joao-kanban";
+          priority = "critical";
+        }
+      ];
+      description = ''
+        List of ntfy topics to subscribe to. Each topic gets a notify-send
+        command that feeds into the desktop notification daemon (SwayNC).
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    home.packages = [ pkgs.ntfy ];
+
+    # Client config with subscription → notify-send mappings.
+    # ntfy subscribe (without args) reads subscriptions from here.
+    xdg.configFile."ntfy/client.yml" = {
+      text = ''
+        # Generated by ndots ntfy-notify module.
+        # Each incoming message spawns a notify-send → your notification daemon.
+        subscribe:
+      '' + lib.concatMapStringsSep "\n" (sub:
+        "  - topic: ${cfg.server}/${sub.topic}\n"
+        + "    command: >-\n"
+        + ''      notify-send -a "Kanban" -u "${sub.priority}" "Kanban Update" "$m"''
+      ) cfg.subscriptions;
+    };
+
+    systemd.user.services.ntfy-notify = {
+      Unit = {
+        Description = "ntfy push notification subscriber (kanban → notify-send)";
+        After = [ "graphical-session.target" ];
+        PartOf = [ "graphical-session.target" ];
+      };
+      Service = {
+        Type = "simple";
+        ExecStart = ''
+          ${pkgs.ntfy}/bin/ntfy subscribe
+        '';
+        Restart = "on-failure";
+        RestartSec = 10;
+      };
+      Install.WantedBy = [ "graphical-session.target" ];
+    };
+  };
+}