feat(workspace): support raw output and pretty printed schema

[springwq]

Complements the Admin full OpenAPI schema generation (https://github.com/feed-mob/feedmob_admin/pull/3244).

Summary

• fm workspace openapi enhancements:
  • Added --raw flag to write the OpenAPI JSON specification verbatim to stdout, suitable for piping (fm workspace openapi --raw > openapi.json).
  • Formats JSON schema with JSON.pretty_generate in human-readable mode (without --json) instead of only printing GET /api/v1/openapi returned HTTP 200..
  • Enforces mutual exclusion between --raw and --json.
• fm workspace request get enhancements:
  • Added --raw flag to output the verbatim response body directly to stdout (matching fm pixel request get --raw).
  • Enforces mutual exclusion between --raw and --json.
• Tests & Documentation:
  • Added 5 unit test cases covering --raw success, human-mode pretty-printing, and --raw + --json validation for both commands.
  • All 121 runs / 614 assertions pass; RuboCop clean.
  • Updated README.md command listings and examples.