feat(ci): Add Fedora RPM package build workflow

Building on the Fedora packaging files from #950, this adds a CI workflow
to automatically build RPM packages for Fedora distributions.

The workflow:
- Builds both binary and debug RPMs using rpkg
- Tests package installation in the CI environment
- Publishes packages to Forgejo's RPM registry
- Uploads artifacts for easy download

Thanks to ginger for providing the initial Fedora build files that made
this CI pipeline possible.

fedora/continuwuity.spec.rpkg

@@ -1,6 +1,5 @@
-# This should be run using rpkg-util: https://docs.pagure.org/rpkg-util
+# This should be run using rpkg: https://docs.pagure.org/rpkg
 # it requires Internet access and is not suitable for Fedora main repos
-# TODO: rpkg-util is no longer maintained, find a replacement
 
 Name:           continuwuity
 Version:        {{{ git_repo_version }}}
@@ -38,7 +37,7 @@ sed -i 's/^offline = true$//' .cargo/config.toml
 %cargo_build
 
 # Here's the one legally required mystery incantation in this file.
-# Some of our dependencies have source files which are (for some reason) marked as excutable.
+# Some of our dependencies have source files which are (for some reason) marked as executable.
 # Files in .cargo/registry/ are copied into /usr/src/ by the debuginfo machinery
 # at the end of the build step, and then the BRP shebang mangling script checks
 # the entire buildroot to find executable files, and fails the build because
@@ -46,7 +45,7 @@ sed -i 's/^offline = true$//' .cargo/config.toml
 # So we have to clear the executable bit on all of them before that happens.
 find .cargo/registry/ -executable -name "*.rs" -exec chmod -x {} +
 
-# TODO: this fails currently because it's forced to run in offline mode	
+# TODO: this fails currently because it's forced to run in offline mode
 # {cargo_license -- --no-dev} > LICENSE.dependencies
 
 %install
@@ -77,4 +76,4 @@ install -Dpm0644 conduwuit-example.toml %{buildroot}%{_sysconfdir}/conduwuit/con
 %systemd_postun_with_restart conduwuit.service
 
 %changelog
-{{{ git_repo_changelog }}}
+{{{ git_repo_changelog }}}