This adds first-class sbt settings for a few google-java-format CLI options that are not part of JavaFormatterOptions, but are still supported by the formatter when invoked through the CLI.

Added settings:

• javafmtSortImports
• javafmtRemoveUnusedImports
• javafmtReflowLongStrings

These are wired through to the forked google-java-format process as:

• --skip-sorting-imports
• --skip-removing-unused-imports
• --skip-reflowing-long-strings

Documentation:

• README now documents the new settings and shows basic configuration examples

Add scripted coverage for each new setting, tested locally (also made them fail).

This keeps javafmtOptions for the upstream JavaFormatterOptions subset, while exposing the additional CLI-only options as dedicated sbt settings.