vlt 1.5.0 Adds Agent Skills Management

Summary

vlt 1.5.0 adds a `vlt skills` command that discovers agent skills in installed dependencies and links them into directories coding agents read, such as `.agents/skills`. The skills come from the package version recorded in the project's lockfile, and the links update as dependencies change. The release also lets developers exclude skills from packages flagged as malware using Socket security data.