feat: use friendly DNS create names with hashed resource stems

[wcgomes]

Summary

Apple container create --name is the container id and DNS hostname. Create names are now the sanitized devcontainer.json name (folder/repo fallback) instead of adev-{base}-{hash12}.

• Create --name is DNS / human identification only — no adev- prefix and no identity hash.
• ${devcontainerId}, product *-ws volumes, and Features tags keep the hashed resource stem from folder/repo basename + hash. Config name does not participate.
• rebuild creates the replacement under the live computed create name and keeps the same resource stem / workspace volume. Idle adev-* names stay until rebuild.
• Foreign occupant of the desired name: TTY asks change the name? [Y/n], then a new full name; persist sanitized name and retry. Non-TTY/--json fail closed. Same-workspace leftover under a different name stays a delete-hint.
• Success digest and JSON drop redundant containerName (Apple --name already is the id).
• README tests badge bumped to 842+.

Commits

• 33a3c02 feat: use friendly DNS create names with hashed resource stems
• a77a4bc fix: omit redundant containerName from success digest and JSON