Var regex allows leading dot / consecutive dots — accepts invalid GitHub slugs

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Var regex allows leading dot / consecutive dots — accepts invalid GitHub slugs

• skills/v4-readiness/SKILL.md:113-114

The regex permits values like `./.git/config` segments, `..`, or leading dashes which GitHub does not accept as owner/repo names. While `gh api` would ultimately reject these, the documentation also says `Anything else → log V4_READINESS_BAD_VAR and exit (no notify, no article)`. Strings like `.../...` slip past the validator and then degrade into V4_READINESS_REMOTE_API_ERROR (itself undocumented). Not a security risk because the value is passed to `gh api` as a URL path segment via gh's own handling, but it weakens the BAD_VAR contract.