The indented string ('''...''') included newlines + spaces in the systemd
unit file, which systemd rejected with 'expected entry key name but got /'.
Use a plain double-quoted string instead so ExecStart stays on one line.
pkgs.ntfy on nixos-26.05 resolves to ntfy 2.7.1 (a different tool that
also ships bin/ntfy but doesn't have a 'subscribe' subcommand).
pkgs.ntfy-sh is the correct ntfy.sh notification client at v2.23.0.
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`.