Release v0.1.4

Switch to regular constructor and expose Load() publicly

New() now returns *Config directly instead of a curried DI constructor,
so config can be created and loaded before the app starts. load() and
loadWithContext() are promoted to exported Load() and LoadWithContext().
service.go is removed as Config no longer implements gas.Service; use
gas.WithServiceInstance[gas.ConfigProvider](cfg) to wire it into the
Gas DI container after loading.

Signed-off-by: Ahmed Kamal <ahmed@ahmedkamal.io>