license under MIT

LICENSE (MIT), installed as /usr/share/doc/terraria-server-manager/copyright
in both packages and with %license in the RPM. README gains a License
section and an up-to-date repository layout and build section.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 0.0.13 - unreleased
 
+- terraria-server-manager is now under the MIT license (`LICENSE`). Both packages include it: `/usr/share/doc/terraria-server-manager/copyright`, and on RPM systems also `/usr/share/licenses/terraria-server-manager/LICENSE`.
 - RPM package for Fedora, RHEL 9+ and compatible systems (AlmaLinux, Rocky Linux), built alongside the `.deb` and published to an RPM repository: add `https://gitea.adbraun.lol/api/packages/adam/rpm.repo` to `/etc/yum.repos.d/` and `sudo dnf install terraria-server-manager` (see the guide's "Installation"). It installs the same files and works the same way as the Debian package. `sudo dnf remove` stops all instances (saving their worlds) and turns off starting at boot, scheduled backups and the daemon; worlds, backups and settings are kept. Build it with `make rpm` (needs `rpmbuild`, also on Debian and Ubuntu).
 - `doctor` checks the firewall when firewalld is running (the default on Fedora and RHEL): it lists instance ports, and the daemon's, that firewalld doesn't allow, with the `firewall-cmd` command to open them. `new` shows that command too. Opening ports is never done automatically.
 - Messages that suggest installing something (`doctor`, `fetch`, and when `python3` or `openssl` is missing) now give the `dnf install` command on Fedora and RHEL instead of `apt install`, with the right package names (`libicu`, `polkit`).