Add Nightbell

[riveerxd]

Adds Nightbell to System, between Network Survey and Nix-on-Droid.

It watches HTTP endpoints from the phone rather than from a server, so there is no backend to run and no account to make, and a failed check arrives as a full-screen alarm instead of a notification.

Apache-2.0, on F-Droid since August as a reproducible build signed with my own key. No ads, no trackers, and no analytics or crash reporting library anywhere in the dependency graph.

One thing I would rather state than have someone find: the app makes a request of its own every six hours, to nightbell.app, asking which version is current. The origin logs those, which is how I have any idea how many installs are running. The user agent is Nightbell/3.14.0 (Android) and it carries a marker on the very first run so a new install can be told from a returning one. There is no device identifier and no install identifier, and it is one request per check rather than a chain of fallbacks. The source is selectable, so it can be pointed at the GitHub API or F-Droid instead of my host, and the whole thing is a switch in Settings, on by default. Everything the app monitors, credentials and target URLs included, stays on the phone.

I wrote it.

[offa]

Thanks for your contribution! The project appears to meet the criteria, and your F-Droid submission is much appreciated. However, since it’s still fairly new, we should give it a little more time before proceeding.