GeezerVison

- Upgrade Scala version from 2.13.12 to 3.7.1 in build.sbt
- Update scalafmt.conf to use Scala 3 dialect and modern formatting rules
- Fix Scala 3 compatibility issues in test files:
  - Update lambda syntax to use parentheses around parameters
  - Remove deprecated underscore suffix from function references
  - Apply Scala 3 formatting with scalafmt

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

- Resolve merge conflict in MessagePackTest.scala by using Scala 3 compatible syntax
- Update scalafmt version from 3.9.4 to 3.9.8
- Apply formatting with updated scalafmt version

- Fix build command to use modern sbt syntax: Test / compile instead of test:compile
- Update Scala version reference to 3.7.1 in testing structure
- Update scalafmt configuration notes to reflect Scala 3 dialect and 100 char limit

- Change specific version reference to 'always use the latest Scala 3 version'
- This ensures the documentation remains current as new Scala 3 versions are released

- Fix sbt command syntax: change test:compile to 'Test / compile'
- Add note about Scala 3 dialect and latest version recommendation
- Ensure developer documentation matches current project configuration

- Change comment from 'Format Scala test code' to 'Format all Scala and sbt code'
- More accurately reflects what scalafmtAll does (formats all Scala files, not just tests)
- Apply change to both README.md and CLAUDE.md for consistency