fix: upgrade to Spring Shell 4

[arnabnandy7]

Summary

Upgrade the shell module from Spring Shell 3.x to Spring Shell 4.0.2 for Spring Boot 4 compatibility.

Fixes #1720.

Changes

• Manage Spring Shell 4.0.2 at the parent POM level.
• Replace removed legacy annotations:
  • @ShellComponent → @Component
  • @ShellMethod → @Command
  • @ShellOption → @Option
• Preserve existing command names and aliases.
• Migrate options to the Spring Shell 4 shortName and longName attributes.
• Update documentation and custom-command examples to use the Spring Shell 4 API.
• Update the shell starter documentation.

Compatibility notes

Spring Shell 4 only supports a single-character short option name. Consequently:

• -td was removed; use --toolDelay.
• -od was removed; use --operationDelay.
• The conflicting set-options -s alias for showPlanning is now -P, consistent with the execute command.

Verification

• Ran the focused embabel-agent-shell test suite:

  mvn -pl embabel-agent-shell -DskipITs test

• Build completed successfully.

Tests run: 52, Failures: 0, Errors: 0, Skipped: 0
BUILD SUCCESS