v0.5.0

• Breaking: migrate the native build hook from hooks 1.x to 2.x (and
  code_assets to 1.2.x). hooks 2.x requires Dart >=3.10, so the SDK lower
  bound rises from 3.6.0 — consumers on Dart 3.6–3.9 should stay on 0.4.x. The
  hook's behaviour is unchanged (it still builds libpackagekit_nc.so via CMake
  and skips cleanly when cmake/ninja/sd-bus are absent); the migration is a
  dependency bump only, verified end to end against a consumer build.
• Drop the native_toolchain_c dependency: it was declared but never imported
  (the hook drives CMake directly rather than CBuilder).