The PHP app runs on Cafe24 shared web hosting -- calling it 'cloud'
was misleading. Renames the directory, the edge client module, and
every doc/script/identifier that used the term.
- cloud/ -> server/ (incl. server/deploy/build_cafe24_package.sh paths)
- edge/cloudclient.py -> edge/serverclient.py, CloudClient -> ServerClient
- cloud/docs/cloud-deploy.md -> server/docs/server-deploy.md
- CLOUD_* env/config keys -> SERVER_*
- tests renamed to match
Tests: PHP 109 pass (4 skipped), pytest 167 pass. dist/ regenerated.
