bakery.toml gains license_file/desktop_file (closing the same gap found
across the rest of the ecosystem) plus hicolor-icon-theme as an optional
dep. Removes packaging/PKGBUILD and .forgejo/workflows/package.yml.
Also fixes release.yml, which has never actually succeeded since the
GTK4->Tauri migration (93c3b88): Cargo.toml moved to src/src/Cargo.toml
(the checkout dir is conventionally named "src", and this repo's own
Rust backend directory is *also* named "src", not the usual src-tauri),
and the Rust build needs frontend/build to already exist (tauri.conf.json's
frontendDist) — that's normally handled by `cargo tauri build`'s
beforeBuildCommand hook, which a plain `cargo build` never runs, so it's
now a separate explicit "build frontend" step. Adds dev-release.yml/
beta-release.yml for the same three-track policy used ecosystem-wide.
Mirrors the build/distribution pattern used by the bread project:
- bakery.toml describes bos-settings as a bakery-managed package
- packaging/arch/PKGBUILD builds and installs the binary via cargo
- packaging/arch/bos-settings.desktop for app launchers
- LICENSE (MIT) required by PKGBUILD
