GroupIndicator

build and release from this repo

- adds the addon, showing the raid group number as an on-screen overlay
- converts the options panel from AceConfig to an RUI dialog behind a Blizzard
  stub page, drops AceConfig and AceGUI
- drops the hand-rolled font value and sorting caches, the RUI font dropdown
  reads LibSharedMedia itself
- adds the three AddonCompartmentFunc TOC lines and the globals they resolve
  to, the click opens the settings window
- adds build.sh, packaging tracked files plus externals into
  dist/GroupIndicator-<version>.zip
- adds .pkgmeta pinning RUI 1.5.0, fetched from its release rather than
  committed, and declares ## X-Curse-Project-ID 1686415
- adds the release workflow, develop builds an alpha, main a beta, a tag a
  release
- adds README.md, RELEASING.md and cf.md
- adds logo.tga with its masters and declares ## IconTexture