[DanielThomas]

Summary

• Make Gradle and Maven help compact option references: a short synopsis followed by consistently indented options, like the JDK tools.
• Keep required selectors and cache behavior beside the relevant options. Both commands end at the help option, with no explanatory tail.
• Keep the README focused on key features, one runtime example per tool, and a short cache summary.
• Document compiler examples, supported options, TSV formats, compatibility, and cache behavior in the Build Tool Projects wiki page. Wiki changes are published separately.
• Keep Maven publishing commands distinct from project queries and make bare jig maven return help successfully, matching Gradle.
• Leave other commands help formatting unchanged.

Depends on #57. This PR targets its branch to keep the help changes separate; retarget to main after #57 merges.

Testing

• Added regression checks for compact help, bounded line lengths, no prose tail, and bare-invocation behavior.
• Gradle/Maven command tests: 93 passed.
• Full suite: 662 passed before the final documentation-only change.
• Inspected both rendered help outputs using the source-built jig.
• Checked README and wiki diffs for whitespace errors.