♻️ Reorganize CI workflows for better maintainability

- Split monolithic ci.yml (900+ lines) into focused workflows:
  - ci.yml: Core CLI lint, tests, build (78 lines)
  - reporter.yml: Reporter visual tests (Vizzly cloud)
  - tui.yml: TUI visual tests (Vizzly cloud)
  - sdk-e2e.yml: All SDK E2E tests (TDD + Cloud mode)
  - sdk-unit.yml: SDK unit tests (conditional on file changes)

- Add cloud mode for Ruby, Storybook, and Static-Site SDKs
- Each workflow has its own status check job for branch protection
- SDK E2E always runs to catch CLI breaking changes
- SDK unit tests only run when that SDK's files change

New secrets needed:
- VIZZLY_RUBY_CLIENT_TOKEN
- VIZZLY_STORYBOOK_CLIENT_TOKEN
- VIZZLY_STATIC_SITE_CLIENT_TOKEN

Author: Robdel12