Release pipeline: cargo-release config + Gitea Actions workflows

- release.toml: one shared workspace version, single vX.Y.Z tag,
  full test suite as the pre-release gate, no crates.io publishing.
- .gitea/workflows/ci.yml: the Woodpecker quality bar (fmt, clippy
  -D warnings, tests) for repos served by act_runner.
- .gitea/workflows/release.yml: on a version tag, build stripped
  release binaries for x86_64 and aarch64 Linux, bundle them with the
  systemd units, rendered man pages and example config, and attach the
  tarballs (+ sha256) to a Gitea release via the API.
- dist/PKGBUILD: point at the repo's new home on project.uhhm.no.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -71,3 +71,14 @@ $ cargo clippy --workspace --all-targets -- -D warnings
 
 The `metered` feature (default on) needs D-Bus at runtime only; build
 with `--no-default-features` for systems without it.
+
+## Releasing
+
+```console
+$ cargo release patch      # or minor / major — see release.toml
+```
+
+This bumps the workspace version, tags `vX.Y.Z`, and pushes; the tag
+triggers `.gitea/workflows/release.yml`, which builds x86_64 and
+aarch64 Linux tarballs (binaries, systemd units, man pages, example
+config) and attaches them to the Gitea release.