Scaffold a new internal domain package named `$ARGUMENTS`.

## Steps

1. Create `internal/$ARGUMENTS/$ARGUMENTS.go`:
   - Package declaration `package $ARGUMENTS`
   - One exported concrete type named after the package's responsibility (e.g. `Service`, `Store`, `Client`, `Parser`)
   - Constructor: `func New(...) *<Type>` — only accept dependencies the type actually needs; leave the signature empty if none are obvious yet
   - At least one exported method stub representing the package's primary operation; return `result.Expect[T]` if the operation can fail
   - Doc comment on every exported symbol (the linter enforces this)

2. Create `internal/$ARGUMENTS/$ARGUMENTS_test.go`:
   - Package: `package $ARGUMENTS_test` (black-box)
   - Declare a minimal interface covering only the methods the test calls
   - Write a manual fake struct that satisfies that interface (no code generation)
   - One table-driven test using `t.Run` and helpers from `gitea.djmil.dev/go/template/pkg/testutil`
   - Use `logger.NewNop()` from `gitea.djmil.dev/go/template/pkg/logger` if logging is needed

## Rules (do not break these)

- Never define an interface inside the package itself — consumers define interfaces
- Never call `.Expect()`, `.Must()`, or `.Expectf()` inside the package — only return `result.Expect[T]`
- No third-party imports
- No hard-coded configuration values

## After scaffolding

Run `make lint test` to verify the files compile and the stub test passes. Report what was created and suggest what the caller should wire in `cmd/app/main.go`.